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Videos uploaded by user “kudvenkat”
Part 33 - C# Tutorial - Difference between abstract classes and interfaces.avi
 
05:15
Text version of the video http://csharp-video-tutorials.blogspot.com/2012/06/part-33-c-tutorial-difference-between.html Slides http://csharp-video-tutorials.blogspot.com/2013/08/part-33-abstract-classes-vs-interfaces.html All C# Text Articles http://csharp-video-tutorials.blogspot.co.uk/p/free-c-video-tutorial-for-beginners.html All C# Slides http://csharp-video-tutorials.blogspot.com/p/c.html Complete C# tutorial https://www.youtube.com/playlist?list=PLAC325451207E3105 All Dot Net and SQL Server Tutorials in English https://www.youtube.com/user/kudvenkat/playlists?view=1&sort=dd All Dot Net and SQL Server Tutorials in Arabic https://www.youtube.com/c/KudvenkatArabic/playlists In this part of the c sharp tutorial we will learn about the differences between abstract classes and interfaces
Views: 330099 kudvenkat
Cross apply and outer apply in sql server
 
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cross apply sql server example sql server outer apply example sql server join table function with parameter sql server inner join table valued function In this video we will discuss cross apply and outer apply in sql server with examples. We want to retrieve all the matching rows between Department and Employee tables. This can be very easily achieved using an Inner Join as shown below. Select D.DepartmentName, E.Name, E.Gender, E.Salary from Department D Inner Join Employee E On D.Id = E.DepartmentId Now if we want to retrieve all the matching rows between Department and Employee tables + the non-matching rows from the LEFT table (Department) This can be very easily achieved using a Left Join as shown below. Select D.DepartmentName, E.Name, E.Gender, E.Salary from Department D Left Join Employee E On D.Id = E.DepartmentId Now let's assume we do not have access to the Employee table. Instead we have access to the following Table Valued function, that returns all employees belonging to a department by Department Id. Create function fn_GetEmployeesByDepartmentId(@DepartmentId int) Returns Table as Return ( Select Id, Name, Gender, Salary, DepartmentId from Employee where DepartmentId = @DepartmentId ) Go The following query returns the employees of the department with Id =1. Select * from fn_GetEmployeesByDepartmentId(1) Now if you try to perform an Inner or Left join between Department table and fn_GetEmployeesByDepartmentId() function you will get an error. Select D.DepartmentName, E.Name, E.Gender, E.Salary from Department D Inner Join fn_GetEmployeesByDepartmentId(D.Id) E On D.Id = E.DepartmentId If you execute the above query you will get the following error Msg 4104, Level 16, State 1, Line 3 The multi-part identifier "D.Id" could not be bound. This is where we use Cross Apply and Outer Apply operators. Cross Apply is semantically equivalent to Inner Join and Outer Apply is semantically equivalent to Left Outer Join. Just like Inner Join, Cross Apply retrieves only the matching rows from the Department table and fn_GetEmployeesByDepartmentId() table valued function. Select D.DepartmentName, E.Name, E.Gender, E.Salary from Department D Cross Apply fn_GetEmployeesByDepartmentId(D.Id) E Just like Left Outer Join, Outer Apply retrieves all matching rows from the Department table and fn_GetEmployeesByDepartmentId() table valued function + non-matching rows from the left table (Department) Select D.DepartmentName, E.Name, E.Gender, E.Salary from Department D Outer Apply fn_GetEmployeesByDepartmentId(D.Id) E How does Cross Apply and Outer Apply work The APPLY operator introduced in SQL Server 2005, is used to join a table to a table-valued function. The Table Valued Function on the right hand side of the APPLY operator gets called for each row from the left (also called outer table) table. Cross Apply returns only matching rows (semantically equivalent to Inner Join) Outer Apply returns matching + non-matching rows (semantically equivalent to Left Outer Join). The unmatched columns of the table valued function will be set to NULL. Text version of the video http://csharp-video-tutorials.blogspot.com/2015/09/cross-apply-and-outer-apply-in-sql.html Slides http://csharp-video-tutorials.blogspot.com/2015/09/cross-apply-and-outer-apply-in-sql_8.html All SQL Server Text Articles http://csharp-video-tutorials.blogspot.com/p/free-sql-server-video-tutorials-for.html All SQL Server Slides http://csharp-video-tutorials.blogspot.com/p/sql-server.html All Dot Net and SQL Server Tutorials in English https://www.youtube.com/user/kudvenkat/playlists?view=1&sort=dd All Dot Net and SQL Server Tutorials in Arabic https://www.youtube.com/c/KudvenkatArabic/playlists
Views: 76107 kudvenkat
Part 36 - C# Tutorial - Delegates in c#.avi
 
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In this c sharp tutorial we will learn the basics of delegates Text version of the video http://csharp-video-tutorials.blogspot.com/2012/06/part-36-c-tutorial-delegates.html Slides http://csharp-video-tutorials.blogspot.com/2013/08/part-36-delegates.html All C# Text Articles http://csharp-video-tutorials.blogspot.co.uk/p/free-c-video-tutorial-for-beginners.html All C# Slides http://csharp-video-tutorials.blogspot.com/p/c.html Complete C# tutorial https://www.youtube.com/playlist?list=PLAC325451207E3105 All Dot Net and SQL Server Tutorials in English https://www.youtube.com/user/kudvenkat/playlists?view=1&sort=dd All Dot Net and SQL Server Tutorials in Arabic https://www.youtube.com/c/KudvenkatArabic/playlists
Views: 401911 kudvenkat
Part 5   ASP NET Web API Content Negotiation
 
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In this video we will discuss Content Negotiation in Web API. Text version of the video http://csharp-video-tutorials.blogspot.com/2016/09/aspnet-web-api-content-negotiation.html Slides http://csharp-video-tutorials.blogspot.com/2016/09/aspnet-web-api-content-negotiation_5.html Dot Net and SQL Server Tutorials https://www.youtube.com/user/kudvenkat/playlists?view=1&sort=dd All ASP.NET Web API Text Articles and Slides http://csharp-video-tutorials.blogspot.com/2016/09/aspnet-web-api-tutorial-for-beginners.html
Views: 178172 kudvenkat
Indexes in sql server   Part 35
 
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In this video we will learn about What are indexes Why do we use indexes Advantages of indexes These concepts are applicable to sql server 2000, 2005 and 2008 Text version of the video http://csharp-video-tutorials.blogspot.com/2012/09/indexes-in-sql-server-part-35.html Slides http://csharp-video-tutorials.blogspot.com/2013/08/part-35-indexes.html All SQL Server Text Articles http://csharp-video-tutorials.blogspot.com/p/free-sql-server-video-tutorials-for.html All SQL Server Slides http://csharp-video-tutorials.blogspot.com/p/sql-server.html All Dot Net and SQL Server Tutorials in English https://www.youtube.com/user/kudvenkat/playlists?view=1&sort=dd All Dot Net and SQL Server Tutorials in Arabic https://www.youtube.com/c/KudvenkatArabic/playlists
Views: 387019 kudvenkat
Part 32 - C# Tutorial - Abstract classes in c#.avi
 
09:50
In this part of the c sharp tutorial we will learn about abstract classes Text version of the video http://csharp-video-tutorials.blogspot.com/2012/06/part-32-c-tutorial-abstract-classes.html Slides http://csharp-video-tutorials.blogspot.com/2013/08/part-32-abstract-classes.html All C# Text Articles http://csharp-video-tutorials.blogspot.co.uk/p/free-c-video-tutorial-for-beginners.html All C# Slides http://csharp-video-tutorials.blogspot.com/p/c.html Complete C# tutorial https://www.youtube.com/playlist?list=PLAC325451207E3105 All Dot Net and SQL Server Tutorials in English https://www.youtube.com/user/kudvenkat/playlists?view=1&sort=dd All Dot Net and SQL Server Tutorials in Arabic https://www.youtube.com/c/KudvenkatArabic/playlists
Views: 286908 kudvenkat
Part 4   Delete duplicate rows in sql
 
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Link for all dot net and sql server video tutorial playlists http://www.youtube.com/user/kudvenkat/playlists Link for slides, code samples and text version of the video http://csharp-video-tutorials.blogspot.com/2014/05/part-4-delete-duplicate-rows-in-sql.html In this video, we will discuss deleting all duplicate rows except one from a sql server table. SQL Script to create Employees table Create table Employees ( ID int, FirstName nvarchar(50), LastName nvarchar(50), Gender nvarchar(50), Salary int ) GO Insert into Employees values (1, 'Mark', 'Hastings', 'Male', 60000) Insert into Employees values (1, 'Mark', 'Hastings', 'Male', 60000) Insert into Employees values (1, 'Mark', 'Hastings', 'Male', 60000) Insert into Employees values (2, 'Mary', 'Lambeth', 'Female', 30000) Insert into Employees values (2, 'Mary', 'Lambeth', 'Female', 30000) Insert into Employees values (3, 'Ben', 'Hoskins', 'Male', 70000) Insert into Employees values (3, 'Ben', 'Hoskins', 'Male', 70000) Insert into Employees values (3, 'Ben', 'Hoskins', 'Male', 70000) The delete query should delete all duplicate rows except one. Here is the SQL query that does the job. PARTITION BY divides the query result set into partitions. WITH EmployeesCTE AS ( SELECT *, ROW_NUMBER()OVER(PARTITION BY ID ORDER BY ID) AS RowNumber FROM Employees ) DELETE FROM EmployeesCTE WHERE RowNumber ] 1
Views: 339932 kudvenkat
Part 24 - C# Tutorial - Difference between method overriding and method hiding.avi
 
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Text version of the video http://csharp-video-tutorials.blogspot.com/2012/06/part-24-c-tutorial-difference-between.html Slides http://csharp-video-tutorials.blogspot.com/2013/08/part-24-method-overriding-vs-method.html All C# Text Articles http://csharp-video-tutorials.blogspot.co.uk/p/free-c-video-tutorial-for-beginners.html All C# Slides http://csharp-video-tutorials.blogspot.com/p/c.html All Dot Net and SQL Server Tutorials in English https://www.youtube.com/user/kudvenkat/playlists?view=1&sort=dd All Dot Net and SQL Server Tutorials in Arabic https://www.youtube.com/c/KudvenkatArabic/playlists In this part of the c sharp tutorial we will learn the difference between method overriding and method hiding
Views: 261536 kudvenkat
Over clause in SQL Server
 
09:13
over partition by in sql server 2008 sql server over clause partition partition by clause in sql server 2008 over partition by clause in sql In this video we will discuss the power and use of Over clause in SQL Server. The OVER clause combined with PARTITION BY is used to break up data into partitions. Syntax : function (...) OVER (PARTITION BY col1, Col2, ...) The specified function operates for each partition. For example : COUNT(Gender) OVER (PARTITION BY Gender) will partition the data by GENDER i.e there will 2 partitions (Male and Female) and then the COUNT() function is applied over each partition. Any of the following functions can be used. Please note this is not the complete list. COUNT(), AVG(), SUM(), MIN(), MAX(), ROW_NUMBER(), RANK(), DENSE_RANK() etc. Example : SQl Script to create Employees table Create Table Employees ( Id int primary key, Name nvarchar(50), Gender nvarchar(10), Salary int ) Go Insert Into Employees Values (1, 'Mark', 'Male', 5000) Insert Into Employees Values (2, 'John', 'Male', 4500) Insert Into Employees Values (3, 'Pam', 'Female', 5500) Insert Into Employees Values (4, 'Sara', 'Female', 4000) Insert Into Employees Values (5, 'Todd', 'Male', 3500) Insert Into Employees Values (6, 'Mary', 'Female', 5000) Insert Into Employees Values (7, 'Ben', 'Male', 6500) Insert Into Employees Values (8, 'Jodi', 'Female', 7000) Insert Into Employees Values (9, 'Tom', 'Male', 5500) Insert Into Employees Values (10, 'Ron', 'Male', 5000) Go Write a query to retrieve total count of employees by Gender. Also in the result we want Average, Minimum and Maximum salary by Gender. This can be very easily achieved using a simple GROUP BY query as show below. SELECT Gender, COUNT(*) AS GenderTotal, AVG(Salary) AS AvgSal, MIN(Salary) AS MinSal, MAX(Salary) AS MaxSal FROM Employees GROUP BY Gender What if we want non-aggregated values (like employee Name and Salary) in result set along with aggregated values You cannot include non-aggregated columns in the GROUP BY query. SELECT Name, Salary, Gender, COUNT(*) AS GenderTotal, AVG(Salary) AS AvgSal, MIN(Salary) AS MinSal, MAX(Salary) AS MaxSal FROM Employees GROUP BY Gender The above query will result in the following error : Column 'Employees.Name' is invalid in the select list because it is not contained in either an aggregate function or the GROUP BY clause One way to achieve this is by including the aggregations in a subquery and then JOINING it with the main query as shown in the example below. Look at the amount of T-SQL code we have to write. SELECT Name, Salary, Employees.Gender, Genders.GenderTotals, Genders.AvgSal, Genders.MinSal, Genders.MaxSal FROM Employees INNER JOIN (SELECT Gender, COUNT(*) AS GenderTotals, AVG(Salary) AS AvgSal, MIN(Salary) AS MinSal, MAX(Salary) AS MaxSal FROM Employees GROUP BY Gender) AS Genders ON Genders.Gender = Employees.Gender Better way of doing this is by using the OVER clause combined with PARTITION BY SELECT Name, Salary, Gender, COUNT(Gender) OVER(PARTITION BY Gender) AS GenderTotals, AVG(Salary) OVER(PARTITION BY Gender) AS AvgSal, MIN(Salary) OVER(PARTITION BY Gender) AS MinSal, MAX(Salary) OVER(PARTITION BY Gender) AS MaxSal FROM Employees Text version of the video http://csharp-video-tutorials.blogspot.com/2015/09/over-clause-in-sql-server.html Slides http://csharp-video-tutorials.blogspot.com/2015/09/over-clause-in-sql-server_29.html All SQL Server Text Articles http://csharp-video-tutorials.blogspot.com/p/free-sql-server-video-tutorials-for.html All SQL Server Slides http://csharp-video-tutorials.blogspot.com/p/sql-server.html All Dot Net and SQL Server Tutorials in English https://www.youtube.com/user/kudvenkat/playlists?view=1&sort=dd All Dot Net and SQL Server Tutorials in Arabic https://www.youtube.com/c/KudvenkatArabic/playlists
Views: 87680 kudvenkat
Part 6  ViewData and ViewBag in mvc
 
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Text version of the video http://csharp-video-tutorials.blogspot.com/2013/04/part-6-viewdata-and-viewbag-in-mvc.html Slides http://csharp-video-tutorials.blogspot.com/2013/09/part-6-view-data-and-view-bag-in-mvc.html All ASP .NET MVC Text Articles http://csharp-video-tutorials.blogspot.com/p/aspnet-mvc-tutorial-for-beginners.html All ASP .NET MVC Slides http://csharp-video-tutorials.blogspot.com/p/aspnet-mvc-slides.html All Dot Net and SQL Server Tutorials in English https://www.youtube.com/user/kudvenkat/playlists?view=1&sort=dd All Dot Net and SQL Server Tutorials in Arabic https://www.youtube.com/c/KudvenkatArabic/playlists In this video we will discuss 1. What is ViewData 2. What is ViewBag 3. Difference between ViewData and ViewBag Both ViewData and ViewBag are used to pass data from a controller to a view. ViewData is a dictionary of objects that are stored and retrieved using strings as keys. The syntax of ViewData is very similar to that of ViewState, SessionState and ApplicationState. // Storing data in ViewData ViewData["YourData"] = "SomeData"; // Retrieving data from ViewData string strData = ViewData["YourData"].ToString(); ViewData does not provide compile time error checking. For example, if you mis-spell the key names you wouldn't get any compile time error. You get to know about the error only at runtime. ViewBag uses the dynamic feature that was introduced in to C# 4. It allows an object to have properties dynamically added to it. Using ViewBag the above code can be rewritten as below. // Storing data in ViewBag ViewBag.YourData = "SomeData"; // Retrieving data from ViewBag string strData = ViewBag.YourData; Just like ViewData, ViewBag does not provide compile time error checking. For example, if you mis-spell the property name, you wouldn't get any compile time error. You get to know about the error only at runtime. Internally ViewBag properties are stored as name/value pairs in the ViewData dictionary. Please Note: To pass data from controller to a view, It's always a good practice to use strongly typed view models instead of using ViewBag & ViewData. Strongly typed view models provide compile time error checking. We will discuss view models in a later video session.
Views: 449083 kudvenkat
Part 1   Introduction to WCF
 
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Link for code samples used in the demo http://csharp-video-tutorials.blogspot.com/2013/11/part-1-introduction-to-wcf.html Link for all dot net and sql server video tutorial playlists http://www.youtube.com/user/kudvenkat/playlists In this video we will discuss What is WCF Why should we use WCF What is WCF? WCF stands for Windows Communication Foundation and is part of .NET 3.0. WCF is Microsoft platform for building distributed and interoperable applications. What is a distributed application? In simple terms a distributed application, is an application where parts of it run on 2 or more computers. Distributed applications are also called as connected systems or applications. Examples: A web application running on one machine and a web service that this application is consuming is running on another machine. An enterprise web application may have the following tiers, and each tier may be running on a different machine 1. Presentation tier 2. Business tier 3. Data Access tier Why build distributed applications? There are several reasons for this 1. An enterprise application may need to use the services provided by other enterprises. For example an ecommerce application may be using paypal service for payments. 2. For better scalability. An enterprise web application may have Presentation tier, Business tier, and Data Access tiert, and each tier may be running on a different machine. What is an interoperable application? An application that can communicate with any other application that is built on any platform and using any programming language is called as an interoperable application. Web services are interoperable, where as .NET remoting services are not. Web services can communicate with any application built on any platform, where as a .NET remoting service can be consumed only by a .net application. What technology choices did we have before WCF to build distributed applications? Enterprise Services Dot Net Remoting Web Services Why should we use WCF? Let's take this scenario We have 2 clients and we need to implement a service a for them. 1. The first client is using a Java application to interact with our service, so for interoperability this client wants messages to be in XML format and the protocol to be HTTP. 2. The second client uses .NET, so for better performance this client wants messages formmated in binary over TCP protocol. Without WCF 1. To satisfy the first client requirement we end up implementing an ASMX web service, and 2. To satisfy the second client requirement we end up implementing a remoting service These are 2 different technologies, and have complete different programming models. So the developers have to learn different technologies. So to unify and bring all these technologies under one roof Microsoft has come up with a single programming model that is called as WCF - Windows Communication Foundation. With WCF, You implement one service and we can configure as many end points as want to support all the client needs. To support the above 2 client requirements, we would configure 2 end points. In the endpoint configuration we can specify the protocols and message formats that we want to use. In Part 2, we will discuss implementing 1. A web service to exchange messages in XML format using HTTP protocol for interoperability. 2. A remoting service to exchange messages in binary format using TCP protocol for performance. Along the way, we will get a feel of how different these technologies are. In Part 3, we will dicuss implementing a single WCF Service and configuring different end points to support different transport protocols and message formats.
Views: 761236 kudvenkat
Clustered and nonclustered indexes in sql server   Part 36
 
16:49
In this video we will learn about 1. Different types of indexes in sql server 2. What are clustered indexes 3. What are NonClustered indexes 4. Difference between clustered and non clustered indexes Text version of the video http://csharp-video-tutorials.blogspot.co.uk/2012/09/clustered-and-non-clustered-indexes.html Slides http://csharp-video-tutorials.blogspot.com/2013/09/part-36-clustered-nonclustered-indexes.html All SQL Server Text Articles http://csharp-video-tutorials.blogspot.com/p/free-sql-server-video-tutorials-for.html All SQL Server Slides http://csharp-video-tutorials.blogspot.com/p/sql-server.html All Dot Net and SQL Server Tutorials in English https://www.youtube.com/user/kudvenkat/playlists?view=1&sort=dd All Dot Net and SQL Server Tutorials in Arabic https://www.youtube.com/c/KudvenkatArabic/playlists
Views: 471860 kudvenkat
Part 3   How does a recursive CTE work
 
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Link for all dot net and sql server video tutorial playlists http://www.youtube.com/user/kudvenkat/playlists Link for slides, code samples and text version of the video http://csharp-video-tutorials.blogspot.com/2014/05/part-3-how-does-recursive-cte-work.html A lot of you have asked to explain, how a recursive CTE work line by line. If you have not watched Part 2 already, I strongly recommend to watch that video first before proceeding. In Part 2 of SQL Server Interview questions and answers video series we discussed recursive CTE to retrieve the organization hierarchy. Let's now discuss how the CTE executes line by line. Step 1: Execute the anchor part and get result R0 Step 2: Execute the recursive member using R0 as input and generate result R1 Step 3: Execute the recursive member using R1 as input and generate result R2 Step 4: Recursion goes on until the recursive member output becomes NULL Step 5: Finally apply UNION ALL on all the results to produce the final output
Views: 154630 kudvenkat
How to become asp net developer
 
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http://csharp-video-tutorials.blogspot.com/2014/09/how-to-become-aspnet-developer.html In this video we will discuss all that you need to know to become a successful asp.net web application developer Essential skills : The following are the essential skills that you need to learn in the order specified to become a web developer 1. Dot Net Basics : Learn what is Dot Net all about and how it works. All dot net developers, irrespective of whether you are a web or windows developer, need to know about these concepts. 2. One Programming language (C# or VB.NET) : You must learn at least on of the programming language (C# or VB.NET) to build dynamic data driven web applications. These videos start from the basics and covers all the advanced aspects of c# programming language that an asp.net web developer needs to know. 3. SQL Server : SQL Server is a database that stores the web application data. You need to learn the SQL programming language to store and retrieve data from the database server, which helps us build data driven web application. 4. ASP.NET : This is the framework that .NET provides to build web applications. 5. ADO.NET : Enables an asp.net web application to communicate with the database to store and retrieve data. 6. ASP.NET GridView - This is one of the widely used data control in an asp.net web application that enables to display, insert, update and delete data. 7. Visual Studio - This is the development tool/software that we use to build Dot Net applications. In addition to the above 7 essential skills, you also need to know the basics of HTML. HTML is very easy to self learn and there are many free resources on the web already. Nice to have skills : These days a lot of organisations are also looking for the following skills in addtion to the above essential skills. If you want to increase the chances of getting your resume shortlisted for an interview call, then you also need to be familiar (if not proficient) with the following technologies. 1. ASP.NET Web Services : ASP.NET Web Services became a legacy technology with the introduction of WCF. However, there are many organisations that are still using ASP.NET web services, so if you want to increase your chances of an interview call you may want to learn this technology as well. Also, learning asp.net web services, makes it easy to learn WCF. 2. WCF : Helps buils service oriented applications. If you are familiar with this and if you can answer the interview questions you almost have the job. 3. ASP.NET MVC - Gives you a powerful, patterns-based way to build dynamic websites that enables a clean separation of concerns and that gives you full control. 3. Entity Framework : This is an ORM framework that enables .NET developers to work with relational data using domain-specific objects. Another nice to have skill. 4. LINQ - Language-Integrated Query (LINQ) is a set of features introduced in Visual Studio 2008 that extends powerful query capabilities to the language syntax of C# and Visual Basic. The different aspects of LINQ are covered in the following tutorials. LINQ LINQ to XML LINQ to SQL In addition to the above 4 nice to have skills, you also need to know jQuery. I don't have a video series on this yet, but there are several resources on the web already. To help you with your interview preparation, I have also started several video series as listed below. C# Interview Questions & Answers Dot Net Written Test Questions & Answers SQL Server Interview Questions & Answers Slides, code samples and text version of the videos are available on my blog. http://csharp-video-tutorials.blogspot.com All these resources are available at no cost. In total there are over 700 videos (150 Hours). This means if you spend 5 hours a day watching these videos in 30 days you have most of the skills required to become a successful asp.net web developer. If you need a video on a concept that you are struggling with or if you have attended an interview and if you need a question to be answered, please leave it as a comment and I shall record and upload video answering it as soon as I can. If you need a DVD with all the videos and slides or if you need to download the videos for offline viewing, please visit the following link. http://pragimtech.com/order.aspx Finally if you feel these videos could help others like you please share on Facebook, Google+ and any other social media you use. Enjoy Coding Venkat
Views: 121625 kudvenkat
Lead and Lag functions in SQL Server 2012
 
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In this video we will discuss about Lead and Lag functions. Lead and Lag functions Introduced in SQL Server 2012 Lead function is used to access subsequent row data along with current row data Lag function is used to access previous row data along with current row data ORDER BY clause is required PARTITION BY clause is optional Syntax LEAD(Column_Name, Offset, Default_Value) OVER (ORDER BY Col1, Col2, ...) LAG(Column_Name, Offset, Default_Value) OVER (ORDER BY Col1, Col2, ...) Offset - Number of rows to lead or lag. Default_Value - The default value to return if the number of rows to lead or lag goes beyond first row or last row in a table or partition. If default value is not specified NULL is returned. We will use the following Employees table for the examples in this video SQL Script to create the Employees table Create Table Employees ( Id int primary key, Name nvarchar(50), Gender nvarchar(10), Salary int ) Go Insert Into Employees Values (1, 'Mark', 'Male', 1000) Insert Into Employees Values (2, 'John', 'Male', 2000) Insert Into Employees Values (3, 'Pam', 'Female', 3000) Insert Into Employees Values (4, 'Sara', 'Female', 4000) Insert Into Employees Values (5, 'Todd', 'Male', 5000) Insert Into Employees Values (6, 'Mary', 'Female', 6000) Insert Into Employees Values (7, 'Ben', 'Male', 7000) Insert Into Employees Values (8, 'Jodi', 'Female', 8000) Insert Into Employees Values (9, 'Tom', 'Male', 9000) Insert Into Employees Values (10, 'Ron', 'Male', 9500) Go Lead and Lag functions example WITHOUT partitions : This example Leads 2 rows and Lags 1 row from the current row. When you are on the first row, LEAD(Salary, 2, -1) allows you to move forward 2 rows and retrieve the salary from the 3rd row. When you are on the first row, LAG(Salary, 1, -1) allows us to move backward 1 row. Since there no rows beyond row 1, Lag function in this case returns the default value -1. When you are on the last row, LEAD(Salary, 2, -1) allows you to move forward 2 rows. Since there no rows beyond the last row 1, Lead function in this case returns the default value -1. When you are on the last row, LAG(Salary, 1, -1) allows us to move backward 1 row and retrieve the salary from the previous row. SELECT Name, Gender, Salary, LEAD(Salary, 2, -1) OVER (ORDER BY Salary) AS Lead_2, LAG(Salary, 1, -1) OVER (ORDER BY Salary) AS Lag_1 FROM Employees Lead and Lag functions example WITH partitions : Notice that in this example, Lead and Lag functions return default value if the number of rows to lead or lag goes beyond first row or last row in the partition. SELECT Name, Gender, Salary, LEAD(Salary, 2, -1) OVER (PARTITION By Gender ORDER BY Salary) AS Lead_2, LAG(Salary, 1, -1) OVER (PARTITION By Gender ORDER BY Salary) AS Lag_1 FROM Employees Text version of the video http://csharp-video-tutorials.blogspot.com/2015/10/lead-and-lag-functions-in-sql-server.html Slides http://csharp-video-tutorials.blogspot.com/2015/10/lead-and-lag-functions-in-sql-server_5.html All SQL Server Text Articles http://csharp-video-tutorials.blogspot.com/p/free-sql-server-video-tutorials-for.html All SQL Server Slides http://csharp-video-tutorials.blogspot.com/p/sql-server.html All Dot Net and SQL Server Tutorials in English https://www.youtube.com/user/kudvenkat/playlists?view=1&sort=dd All Dot Net and SQL Server Tutorials in Arabic https://www.youtube.com/c/KudvenkatArabic/playlists
Views: 50775 kudvenkat
Database normalization   Part 52
 
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In this video we will learn about, database normalization, different normal forms, problems of data redundancy, first normal form, that is how to put a table in 1 NF. Text version of the video http://csharp-video-tutorials.blogspot.com/2012/09/database-normalization-part-52.html Slides http://csharp-video-tutorials.blogspot.com/2013/09/part-52-normalization.html All SQL Server Text Articles http://csharp-video-tutorials.blogspot.com/p/free-sql-server-video-tutorials-for.html All SQL Server Slides http://csharp-video-tutorials.blogspot.com/p/sql-server.html All Dot Net and SQL Server Tutorials in English https://www.youtube.com/user/kudvenkat/playlists?view=1&sort=dd All Dot Net and SQL Server Tutorials in Arabic https://www.youtube.com/c/KudvenkatArabic/playlists
Views: 186377 kudvenkat
C# abstract class virtual method
 
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Text version of the video http://csharp-video-tutorials.blogspot.com/2016/10/c-abstract-class-virtual-method.html Slides http://csharp-video-tutorials.blogspot.com/2016/10/c-abstract-class-virtual-method_24.html All C# Interview Questions Text Articles & Slides http://csharp-video-tutorials.blogspot.com/p/c-interview-questions.html All Dot Net and SQL Server Tutorials in English https://www.youtube.com/user/kudvenkat/playlists?view=1&sort=dd All Dot Net and SQL Server Tutorials in Arabic https://www.youtube.com/c/KudvenkatArabic/playlists
Views: 62347 kudvenkat
Installing aspnet mvc - Part 1
 
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Text version of the video http://csharp-video-tutorials.blogspot.com/2013/04/installing-aspnet-mvc-part-1.html Slides http://csharp-video-tutorials.blogspot.com/2013/09/part-1-installing-aspnet-mvc.html All ASP .NET MVC Text Articles http://csharp-video-tutorials.blogspot.com/p/aspnet-mvc-tutorial-for-beginners.html All ASP .NET MVC Slides http://csharp-video-tutorials.blogspot.com/p/aspnet-mvc-slides.html ASP.NET MVC Playlist https://www.youtube.com/playlist?list=PL4cyC4G0M1RQAV0xCaEjfwAeaFaUuHXuf All Dot Net and SQL Server Tutorials in English https://www.youtube.com/user/kudvenkat/playlists?view=1&sort=dd All Dot Net and SQL Server Tutorials in Arabic https://www.youtube.com/c/KudvenkatArabic/playlists In this video we will discuss about installing asp.net mvc. Before installing asp.net mvc, first let's determine what version is already installed. Go to "Control Panel" and click on "Programs and Features". If you want to create asp.net mvc 3 or 4 applications, then please download and install asp.net mvc 3 and 4 from the following locations. ASP.NET MVC 3 http://www.asp.net/mvc/mvc3 ASP.NET MVC 4 http://www.asp.net/mvc/mvc4 When you create a new project, make sure you have .NET Framework 4 selected in the drop down list. If you have any other earlier .net framework versions selected, then ASP.NET MVC 3 Web Application and ASP.NET MVC 4 Web Application templates will not be available.
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Part 3   Why and when should we use an abstract class
 
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Link for code samples used in the demo http://csharp-video-tutorials.blogspot.com/2013/09/part-3-why-and-when-should-we-use.html Link for csharp, asp.net, ado.net, dotnet basics, mvc and sql server video tutorial playlists http://www.youtube.com/user/kudvenkat/playlists This question can also be asked in a slightly different way Give an example of where we could use an abstract class? Let us understand when to use an abstract class with an example. An organisation has 2 types of employees 1. FullTimeEmployee 2. ContractEmployee We would create an abstract class, when want to move the common functionality of 2 or more related classes into a base class and when, we don't want that base class to be instantiated.
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Part 10   What happens if finally block throws an exception
 
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Link for code samples used in the demo http://csharp-video-tutorials.blogspot.com/2013/10/part-10-what-happens-if-finally-block.html Link for all dot net and sql server video tutorial playlists http://www.youtube.com/user/kudvenkat/playlists This question can also be asked in a slightly different way How to handle exceptions that occur in finally block The exception propagates up, and should be handled at a higher level. If the exception is not handled at the higher level, the application crashes. The "finally" block execution stops at the point where the exception is thrown. In the example below, notice that the "finally" block in "Hello()" method throws an exception. Hello() method is being called in the Main() method and we don't have any exception handling mechanism in place in the Main() method. So, the application crashes with the exception. public class Program { public static void Main() { Hello(); } public static void Hello() { try { // Some code } catch { // Some code } finally { Console.WriteLine("This line will be executed"); int result = Convert.ToInt32("TEN"); Console.WriteLine("This line will NOT be executed"); } } } On the other hand, if you include exception handling mechanism(try/catch) in the Main() method, then you will have the opportunity to handle the exception. public static void Main() { try { Hello(); } catch (Exception ex) { // Process and log the exception Console.WriteLine(ex.Message); } } Irrespective of whether there is an exception or not "finally" block is guaranteed to execute. 1. If the "finally" block is being executed after an exception has occurred in the try block, 2. and if that exception is not handled 3. and if the finally block throws an exception Then the original exception that occurred in the try block is lost. Here is an example: public class Program { public static void Main() { try { Hello(); } catch (Exception ex) { Console.WriteLine(ex.Message); } } public static void Hello() { try { // This exception will be lost throw new Exception("Exception in TRY block"); } finally { throw new Exception("Exception in FINALLY block"); } } }
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Group by in sql server - Part 11
 
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In this video we will learn 1. Grouping rows using GROUP BY 2. Filtering Groups 3. Difference between WHERE and HAVING clause in sql server Text version of the video http://csharp-video-tutorials.blogspot.com/2012/08/group-by-part-11.html Slides http://csharp-video-tutorials.blogspot.com/2013/08/part-11-group-by.html All SQL Server Text Articles http://csharp-video-tutorials.blogspot.com/p/free-sql-server-video-tutorials-for.html All SQL Server Slides http://csharp-video-tutorials.blogspot.com/p/sql-server.html All Dot Net and SQL Server Tutorials in English https://www.youtube.com/user/kudvenkat/playlists?view=1&sort=dd All Dot Net and SQL Server Tutorials in Arabic https://www.youtube.com/c/KudvenkatArabic/playlists
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Part 71   childactiononly attribute in mvc
 
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Link for code samples used in the demo http://csharp-video-tutorials.blogspot.com/2013/08/part-71-childactiononly-attribute-in-mvc.html Link for csharp, asp.net, ado.net, dotnet basics, mvc and sql server video tutorial playlists http://www.youtube.com/user/kudvenkat/playlists In this video, we will discuss childactiononly attribute in asp.net mvc. Let us understand this with an example. Step 1: Create a blank asp.net mvc 4 application Step 2: Add HomeController. Copy and paste the following code. public class HomeController : Controller { // Public action method that can be invoked using a URL request public ActionResult Index() { return View(); } // This method is accessible only by a child request. A runtime // exception will be thrown if a URL request is made to this method [ChildActionOnly] public ActionResult Countries(List[String] countryData) { return View(countryData); } } Step 3: Right click on the "Countries()" action method and add "Countries" view. This view will render the given list of strings as an un-ordered list. @model List[string] @foreach (string country in Model) { [ul] [li] [b] @country [/b] [/li] [/ul] } Step 4: Right click on the "Index()" action method and add "Index" view. Copy and paste the following code. Notice that, to invoke childaction, we are using Action() HTML Helper. [h2]Countries List[/h2] @Html.Action("Countries", new { countryData = new List[string]() { "US", "UK", "India" } }) Please Note: Child actions can also be invoked using "RenderAction()" HTMl helper as shown below. @{ Html.RenderAction("Countries", new { countryData = new List[string]() { "US", "UK", "India" } }); } We discussed the difference between Action() and RenderAction() in Part XX of MVC Tutorial series. Points to remember about "ChildActionOnly" attribute 1. Any action method that is decorated with [ChildActionOnly] attribute is a child action method. 2. Child action methods will not respond to URL requests. If an attempt is made, a runtime error will be thrown stating - Child action is accessible only by a child request. 3. Child action methods can be invoked by making child request from a view using "Action()" and "RenderAction()" html helpers. 4. An action method doesn't need to have [ChildActionOnly] attribute to be used as a child action, but use this attribute to prevent if you want to prevent the action method from being invoked as a result of a user request. 5. Child actions are typically associated with partial views, although this is not compulsory. 6. Child action methods are different from NonAction methods, in that NonAction methods cannot be invoked using Action() or RenderAction() helpers. We discussed NonAction methods in Part 70 of ASP.NET MVC tutorial series. 7. Using child action methods, it is possible to cache portions of a view. This is the main advantage of child action methods. We will cover this when we discuss [OutputCache] attribute. Make sure to replace [ with LESSTHAN and ] with GREATERTHAN symbol.
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AngularJS tutorial -  What is AngularJS
 
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AngularJS tutorial - What is AngularJS In this video we will discuss What is AngularJS Benefits of AngularJS A simple AngularJS example What is AngularJS AngularJS is a JavaScript framework that helps build applications that run in a web browser. Who developed AngularJS Google is the company that developed AngularJS. AngularJS is an open source project, which means it can be be freely used, changed, and shared by anyone. AngularJS is an excellent framework for building both Single Page Applications (SPA) and Line of Business Applications. Many companies are using Angular today, and there are many public facing web sites that are built with angular. There is a website, https://www.madewithangular.com, that has the list of web sites that are built using AngularJS. Within this list you can find many popular websites. What are the benefits of using AngularJS 1. Dependency Injection : Dependency Injection is something AngularJS does quite well. If you are new to Dependency Injection, don't worry, we will discuss it in detail with examples in a later video. 2. Two Way Data-Binding : One of the most useful feature in AngularJS is the Two Way Data-Binding. The Two Way Data-Binding, keeps the model and the view in sync at all times, that is a change in the model updates the view and a change in the view updates the model. 3. Testing : Testing is an area where Angular really shines. Angular is designed with testing in mind right from the start. Angular makes it very easy to test any of it's components through both unit testing and end to end testing. So there's really no excuse for not testing any of your angular application code. 4. Model View Controller : With angular it is very easy to develop applications in a clean MVC way. All you have to do is split your application code into MVC components. The rest, that is managing those components and connecting them together is done by angular. 5. Many more benefits like controlling the behaviour of DOM elements using directives and the flexibility that angular filters provide. We will discuss directives, filters, Modules, Routes etc with examples in our upcoming videos in this series. To build angular applications you only need one script file and that is angular.js. To get the script file visit https://angularjs.org. From here 1. You can download the angular script file 2. CDN link - We discussed the benefits of using CDN in Part 3 of jQuery tutorial. 3. Various resources to learn angular - Here you will find videos, Free courses, Tutorials and Case Studies. You will also find API reference which is extremeley useful. To get started with angular 1. Add a reference to the angular script 2. Include ng-app attribute What is ng-app In angular, ng-app is called a directive. There are many directives in angular. You can find the complete list of directives on https://angularjs.org. The ng prefix in the directive stands for angular. The ng-app directive is a starting point of AngularJS Application. Angular framework will first check for ng-app directive in an HTML page after the entire page is loaded. If ng-app directive is found, angular bootstraps itself and starts to manage the section of the page that has the ng-app directive. So the obvious next question is, where to place the ng-app directive on the page It should be placed at the root of the HTML document, that is at the [html] tag level or at the [body] tag level, so that angular can control the entire page. However, there is nothing stopping you from placing it on any other HTML element with in the page. When you do this only that element and it's children are managed by angular. Double curly braces are called binding expressions in angular. These All the following are valid expressions in angular {{ 1 == 1 }} - Evaluates to true {{ { name: 'David', age : '30' }.name }} - Returns the name property value {{ ['Mark', 'David', 'Sara'][2] }} - Returns the 2nd element from the array Link for all dot net and sql server video tutorial playlists https://www.youtube.com/user/kudvenkat/playlists?sort=dd&view=1 Link for slides, code samples and text version of the video http://csharp-video-tutorials.blogspot.com/2015/10/what-is-angularjs.html
Views: 1692766 kudvenkat
Difference between AngularJS, Angular 2 and Angular 4
 
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Text version of the video http://csharp-video-tutorials.blogspot.com/2017/09/difference-between-angularjs-angular-2.html Slides http://csharp-video-tutorials.blogspot.com/2017/09/difference-between-angularjs-angular-2_13.html Angular 2 Tutorial playlist https://www.youtube.com/playlist?list=PL6n9fhu94yhWqGD8BuKuX-VTKqlNBj-m6 Angular 2 Text articles and slides http://csharp-video-tutorials.blogspot.com/2017/06/angular-2-tutorial-for-beginners_12.html All Dot Net and SQL Server Tutorials in English https://www.youtube.com/user/kudvenkat/playlists?view=1&sort=dd All Dot Net and SQL Server Tutorials in Arabic https://www.youtube.com/c/KudvenkatArabic/playlists So far Google has released 3 versions of Angular Version Year ------------ ------ AngularJS 2010 Angular 2 2016 Angular 4 2017 What is the difference between AngularJS and Angular 2 The first version of Angular is called AngularJS and was released in the year 2010. Some people call it Angular 1, but it is officially called AngularJS. Angular 2 is released in the year 2016. The most important thing to keep in mind is that, Angular 2 is not a simple upgrade from angular 1. Angular 2 is completely rewritten from the ground up and as a result the way we write applications with AngularJS and Angular 2 is very different. From a performance standpoint, Angular 2 is 5 times faster compared to AngularJS. AngularJS was not built for mobile devices, where as Angular 2 on the other hand is designed from the ground up with mobile support in mind. With Angular 2 we have more language choices. In additon to nativa JavaScript we can use TypeScript, Dart, PureScript, Elm, etc. Angular 4 is released in 2017. So, What is the difference between Angular 2 and Angular 4 If you have worked with both Angular 1 and Angular 2, then you already know that the API's and patterns that we use to build applications are very different between these 2 versions. From a developer stand point, it is like learning 2 different frameworks. Since Angular 2 is a complete rewrite from Angular 1, moving from Angular 1 to Angular 2 is a total breaking change. However, changing from Angular 2 to Angular 4 and even future versions of Angular, won’t be like changing from Angular 1. It won’t be a complete rewrite, it will simply be a change in some core libraries. From a developer standpoint, building an application using Angular 2 and Angular 4 is not very different. We still use the same concepts and patterns. Angular 4 is simply, the next version of Angular 2. The underlying concepts are still the same and if you have already learnt Angular 2 then you’re well prepared to switch to Angular 4. The most important point to keep in mind is, Angular 4 is backwards compatible with Angular 2 for most applications. What has changed and what is new in Angular 4 Some under the hood changes to reduce the size of the AOT (Ahead-of-Time) compiler generated code. Migrating to Angular 4 may reduce the production bundles by hundreds of kilobytes. As a developer this change will not affect the way we write angular applications in any way. TypeScript 2.1 and 2.2 compatibility. Angular is updated with a more recent version of TypeScript, for better type checking throughout our application. Up until Angular 4, only TypeScript 1.8 was supported. With Angular 4, we can use typescript 2.1 or 2.2 which means we can use all the new features of TypeScript with Angular 4. Animation features are pulled out of @angular/core and are moved into their own package. This means that if you don’t use animations, this extra code will not end up in your production bundles. On the other hand, if you do have animations in your application, you may have to change your existing code to pull the animation features from the animations package. We can now use an if/else style syntax with *ngIf structural directive. In Angular 2, to implement if/else logic, we use 2 *ngIf structural directives. With Angular 4, we can use it's new if/else style syntax with *ngIf structural directive. We will discuss an example of this in our upcoming videos. What happened to Angular 3. Why did we move straight from Angular 2 to Angular 4. What is the reason for skipping Angular 3. Except the Router library, all the other Angular core libraries are versioned the same way and are shipped as NPM packages as you can see below. While all the other core angular packages are at Version 2, the router library is already at Version 3. Due to this misalignment of the router package’s version, the angular team decided to go straight for Angular v4. This way, all the core packages are aligned which will be easier to maintain and help avoid confusion in the future. Common Questions Do I have to learn AngularJS 1 before learning Angular 2 Do I have to learn Angular 2 before learning Angular 4
Views: 84489 kudvenkat
Part 30 - C# Tutorial - Interfaces in c#.avi
 
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In this part of the c sharp tutorial we will learn about interfaces Text version of the video http://csharp-video-tutorials.blogspot.com/2012/06/part-30-c-tutorial-interfaces-in-c.html Slides http://csharp-video-tutorials.blogspot.com/2013/08/part-30-introduction-to-interfaces.html All C# Text Articles http://csharp-video-tutorials.blogspot.co.uk/p/free-c-video-tutorial-for-beginners.html All C# Slides http://csharp-video-tutorials.blogspot.com/p/c.html Complete C# tutorial https://www.youtube.com/playlist?list=PLAC325451207E3105 All Dot Net and SQL Server Tutorials in English https://www.youtube.com/user/kudvenkat/playlists?view=1&sort=dd All Dot Net and SQL Server Tutorials in Arabic https://www.youtube.com/c/KudvenkatArabic/playlists
Views: 452246 kudvenkat
What is bootstrap
 
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twitter bootstrap tutorial for beginners twitter bootstrap for beginners benefits of bootstrap framework advantages of bootstrap framework twitter bootstrap benefits what is responsive web design what is responsive website what is responsive design use of bootstrap responsive web development responsive web app In this video we will discuss 1. What is bootstrap 2. Advantages of using bootstrap Bootstrap is a free, open-source and is the most popular HTML, CSS, and JavaScript framework developed by twitter for creating responsive web applications. It includes HTML and CSS based design templates for common user interface components like Buttons, Dropdowns, Typography, Tabs, Forms, Tables, Navigations, Alerts, Modals, Accordion, Carousel etc. along with optional JavaScript extensions. Bootstrap framework is based on open standards - HTML, CSS and JavaScript. This means bootstrap can be used with any server side technology and any platform. You can use it with any web application built with any server side technology like ASP.NET, JAVA, PHP etc. What are the advantages of using bootstrap Supports responsive design : One of the greatest advantages of using bootstrap is that it helps us create responsive web applications faster and easier. So the obvious question that comes to our mind is, what is a responsive web application? A responsive web application automatically adapts to different screen sizes (i.e desktop computers, laptops, tablets. mobile phones etc). A responsive application provides optimal viewing and interaction experience i.e easy reading and navigation with a minimum of resizing, panning, and scrolling across a wide range of devices. So you don't have to worry about your application not being compatible with multiple devices. The images at the following links shows how a responsive and non-responsive application looks like on a mobile device. http://www.webnersolutions.com/wp-content/uploads/2015/08/responsive-vs-non-responsive-web-design1.jpg At the following link is a live responsive application example. Notice as we resize the browser, the content automatically adpats to the screen size. http://bootstrapdocs.com/v3.0.3/docs/examples/jumbotron/ Saves lot of development time : One of the biggest advantages of using Bootstrap is that it saves lot of development time. Instead of writing code from the scratch, bootstrap offers ready made blocks of code that you can use and customize to suit your application requirements. There are also many websites out there that offer free and paid Bootstrap themes that saves even more development time. Consistency : Bootstrap was developed by Twitter to encourage consistency across thier internal tools by giving their developers a centralised development code. Since all the developers are working using a centralised code, the end result is consistent regardless of who’s working on the project and which web browser is being used. Customizable : If you are using only a few features of bootstrap, you can customize to download only those features using the following bootstrap customize page. http://getbootstrap.com/customize/ Support : As Bootstrap is the most popular framework, it has a very large community base and excellent documentation. Bootstrap's excellent documentation, examples and demos helps a developer learn bootstrap quickly even if you are new to it. If you ever run into an issue you will usually get help quickly and easily from the vast online community and web forums. In our next video we will discuss, downloading, setting up and understanding different bootstrap components. Please stay tuned. Link for all dot net and sql server video tutorial playlists https://www.youtube.com/user/kudvenkat/playlists?sort=dd&view=1 Link for slides, code samples and text version of the video http://csharp-video-tutorials.blogspot.com/2016/05/what-is-bootstrap.html
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Part 9   Call an abstract method from an abstract class constructor
 
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Link for code samples used in the demo http://csharp-video-tutorials.blogspot.com/2013/10/part-9-call-abstract-method-from.html Link for csharp, asp.net, ado.net, dotnet basics, mvc and sql server video tutorial playlists http://www.youtube.com/user/kudvenkat/playlists Can you call an abstract method from an abstract class constructor? If so, what is the use of it? Yes, an abstract method can be called from an abstract class constructor. Here is an example. public class Program { public static void Main() { CorporateCustomer CC = new CorporateCustomer(); SavingsCustomer SC = new SavingsCustomer(); } } public abstract class Customer { protected Customer() { Print(); } public abstract void Print(); } public class CorporateCustomer : Customer { public override void Print() { Console.WriteLine("CorporateCustomer Print() method implementation called"); } } public class SavingsCustomer : Customer { public override void Print() { Console.WriteLine("SavingsCustomer Print() method implementation called"); } } An abstract method in an abstract class does not have any implementation, so what is the use of calling it from the abstract class constructor? If you want the abstract method to be invoked automatically whenever an instance of the class that is derived from the abstract class is created, then we would call it in the constructor of the abstract class.
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Part 3   Extension Methods in C#
 
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Link for all dot net and sql server video tutorial playlists http://www.youtube.com/user/kudvenkat/playlists Link for slides, code samples and text version of the video http://csharp-video-tutorials.blogspot.com/2014/07/part-3-extension-methods-in-c.html In this video we will discuss 1. What are Extension Methods 2. How to implement extension methods What are Extension Methods According to MSDN, Extension methods enable you to "add" methods to existing types without creating a new derived type, recompiling, or otherwise modifying the original type. Extension methods are a special kind of static method, but they are called as if they were instance methods on the extended type. For client code written in C# and Visual Basic, there is no apparent difference between calling an extension method and the methods that are actually defined in a type. Let us understand what this definition actually means. LINQ's standard query operators (select, where etc ) are implemented in Enumerable class as extension methods on the IEnumerable[T] interface. Now look at the following query List[int] Numbers = new List[int] { 1, 2, 3 ,4, 5, 6, 7, 8, 9, 10 }; IEnumerable[int] EvenNumbers = Numbers.Where(n =] n % 2 == 0); Inspite of Where() method not belonging to List[T] class, we are still able to use it as though it belong to List[T] class. This is possible because Where() method is implemented as extension method in IEnumerable[T] interface and List[T] implements IEnumerable[T] interface. How to implement extension methods We want to define a method in the string class (let's call it ChangeFirstLetterCase), which will change the case of the first letter of the string. For example, if the first letter of the string is lowercase the function should change it to uppercase and viceversa. We want to be able to call this function on the string object as shown below. string result = strName.ChangeFirstLetterCase(); Defining ChangeFirstLetterCase() method directly in the string class is not possible as we don't own the string class. It belongs to .NET framework. Another alternative is to write a wrapper class as shown below. public class StringHelper { public static string ChangeFirstLetterCase(string inputString) { if (inputString.Length ] 0) { char[] charArray = inputString.ToCharArray(); charArray[0] = char.IsUpper(charArray[0]) ? char.ToLower(charArray[0]) : char.ToUpper(charArray[0]); return new string(charArray); } return inputString; } } Wrapper class works, but the problem is, we cannot call ChangeFirstLetterCase() method using the following syntax. string result = strName.ChangeFirstLetterCase(); Instead we have to call it as shown below. string result = StringHelper.ChangeFirstLetterCase(strName); Convert ChangeFirstLetterCase() method to an extension method to be able to call it using the following syntax, as though it belongs to string class. string result = strName.ChangeFirstLetterCase(); To convert ChangeFirstLetterCase() method to an extension method, make the following 2 changes 1. Make StringHelper static class 2. The type the method extends should be passed as a first parameter with this keyword preceeding it. With these 2 changes, we should be able to call this extension method in the same way we call an instance method. Notice that the extension method shows up in the intellisense as well, but with a different visual clue. string result = strName.ChangeFirstLetterCase(); Please note that, we should still be able to call this extension method using wrapper class style syntax. In fact, behind the scene this is how the method actually gets called. Extension methods are just a syntactic sugar. string result = StringHelper.ChangeFirstLetterCase(strName); So, this means we should also be able to call LINQ extension methods (select, where etc), using wrapper class style syntax. Since all LINQ extension methods are defined in Enumerable class, the syntax will be as shown below. List[int] Numbers = new List[int] { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 }; IEnumerable[int] EvenNumbers = Enumerable.Where(Numbers, n =] n % 2 == 0);
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Rank and Dense Rank in SQL Server
 
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rank and dense_rank example difference between rank and dense_rank with example rank vs dense_rank in sql server 2008 sql server difference between rank and dense_rank In this video we will discuss Rank and Dense_Rank functions in SQL Server Rank and Dense_Rank functions Introduced in SQL Server 2005 Returns a rank starting at 1 based on the ordering of rows imposed by the ORDER BY clause ORDER BY clause is required PARTITION BY clause is optional When the data is partitioned, rank is reset to 1 when the partition changes Difference between Rank and Dense_Rank functions Rank function skips ranking(s) if there is a tie where as Dense_Rank will not. For example : If you have 2 rows at rank 1 and you have 5 rows in total. RANK() returns - 1, 1, 3, 4, 5 DENSE_RANK returns - 1, 1, 2, 3, 4 Syntax : RANK() OVER (ORDER BY Col1, Col2, ...) DENSE_RANK() OVER (ORDER BY Col1, Col2, ...) RANK() and DENSE_RANK() functions without PARTITION BY clause : In this example, data is not partitioned, so RANK() function provides a consecutive numbering except when there is a tie. Rank 2 is skipped as there are 2 rows at rank 1. The third row gets rank 3. DENSE_RANK() on the other hand will not skip ranks if there is a tie. The first 2 rows get rank 1. Third row gets rank 2. SELECT Name, Salary, Gender, RANK() OVER (ORDER BY Salary DESC) AS [Rank], DENSE_RANK() OVER (ORDER BY Salary DESC) AS DenseRank FROM Employees RANK() and DENSE_RANK() functions with PARTITION BY clause : Notice when the partition changes from Female to Male Rank is reset to 1 SELECT Name, Salary, Gender, RANK() OVER (PARTITION BY Gender ORDER BY Salary DESC) AS [Rank], DENSE_RANK() OVER (PARTITION BY Gender ORDER BY Salary DESC) AS DenseRank FROM Employees Use case for RANK and DENSE_RANK functions : Both these functions can be used to find Nth highest salary. However, which function to use depends on what you want to do when there is a tie. Let me explain with an example. If there are 2 employees with the FIRST highest salary, there are 2 different business cases 1. If your business case is, not to produce any result for the SECOND highest salary, then use RANK function 2. If your business case is to return the next Salary after the tied rows as the SECOND highest Salary, then use DENSE_RANK function Since we have 2 Employees with the FIRST highest salary. Rank() function will not return any rows for the SECOND highest Salary. WITH Result AS ( SELECT Salary, RANK() OVER (ORDER BY Salary DESC) AS Salary_Rank FROM Employees ) SELECT TOP 1 Salary FROM Result WHERE Salary_Rank = 2 Though we have 2 Employees with the FIRST highest salary. Dense_Rank() function returns, the next Salary after the tied rows as the SECOND highest Salary WITH Result AS ( SELECT Salary, DENSE_RANK() OVER (ORDER BY Salary DESC) AS Salary_Rank FROM Employees ) SELECT TOP 1 Salary FROM Result WHERE Salary_Rank = 2 You can also use RANK and DENSE_RANK functions to find the Nth highest Salary among Male or Female employee groups. The following query finds the 3rd highest salary amount paid among the Female employees group WITH Result AS ( SELECT Salary, Gender, DENSE_RANK() OVER (PARTITION BY Gender ORDER BY Salary DESC) AS Salary_Rank FROM Employees ) SELECT TOP 1 Salary FROM Result WHERE Salary_Rank = 3 AND Gender = 'Female' Text version of the video http://csharp-video-tutorials.blogspot.com/2015/10/rank-and-denserank-in-sql-server.html Slides http://csharp-video-tutorials.blogspot.com/2015/10/rank-and-denserank-in-sql-server_1.html All SQL Server Text Articles http://csharp-video-tutorials.blogspot.com/p/free-sql-server-video-tutorials-for.html All SQL Server Slides http://csharp-video-tutorials.blogspot.com/p/sql-server.html All Dot Net and SQL Server Tutorials in English https://www.youtube.com/user/kudvenkat/playlists?view=1&sort=dd All Dot Net and SQL Server Tutorials in Arabic https://www.youtube.com/c/KudvenkatArabic/playlists
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Pivot in sql server 2008   Part 54
 
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In this video we will learn about pivot operator. Pivot is a sql server operator that can be used to turn unique values from one column, into multiple columns in the output, there by effectively rotating a table. Text version of the video http://csharp-video-tutorials.blogspot.com/2012/10/pivot-operator-in-sql-server-part-54.html Slides http://csharp-video-tutorials.blogspot.com/2013/09/part-54-pivot-in-sql-server-2008.html All SQL Server Text Articles http://csharp-video-tutorials.blogspot.com/p/free-sql-server-video-tutorials-for.html All SQL Server Slides http://csharp-video-tutorials.blogspot.com/p/sql-server.html All Dot Net and SQL Server Tutorials in English https://www.youtube.com/user/kudvenkat/playlists?view=1&sort=dd All Dot Net and SQL Server Tutorials in Arabic https://www.youtube.com/c/KudvenkatArabic/playlists
Views: 186160 kudvenkat
Self join in sql server - Part 14
 
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In this video we will learn about 1. Self Join - Joining a table with itself 2. Self Join is not a different type of join. It can be classified as Inner Self Join, Outer Self Join (Left, Right and Full), or Cross Self Join. Text version of the video http://csharp-video-tutorials.blogspot.com/2012/08/self-join-in-sql-server-part-14.html Slides http://csharp-video-tutorials.blogspot.com/2013/08/part-14-self-join.html All SQL Server Text Articles http://csharp-video-tutorials.blogspot.com/p/free-sql-server-video-tutorials-for.html All SQL Server Slides http://csharp-video-tutorials.blogspot.com/p/sql-server.html All Dot Net and SQL Server Tutorials in English https://www.youtube.com/user/kudvenkat/playlists?view=1&sort=dd All Dot Net and SQL Server Tutorials in Arabic https://www.youtube.com/c/KudvenkatArabic/playlists
Views: 348318 kudvenkat
Part 26   What is a windows service
 
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Link for code samples used in the demo http://csharp-video-tutorials.blogspot.com/2014/02/part-26-what-is-windows-service_8.html Link for all dot net and sql server video tutorial playlists http://www.youtube.com/user/kudvenkat/playlists In this video, we will discuss 1. What is a windows service and how do they differe from regular applications and programs 2. How to view all the services installed on a windows machine 3. What is the use of windows services 4. When would an asp.net developer use a windows service What is a windows service and how do they differ from regular applications and programs A windows service is similar to any other program or application running on a windows machine. The following are the differences between a windows service and a regular application 1. Windows service runs in the background 2. They can be configured to start automatically when the system starts 3. They don't have user interface. How to view all the services installed on a windows machine 1. Open run windows by pressing Windows + R key 2. Type services.msc and press enter 3. The services window should display all the services installed on your computer What is the use of windows services Windows services provide core operating system features such as Event Logging - Windows Event Log Service Providing Security - Windows Firewall Service Error reporting - Windows Error Reporting Service When would an asp.net developer use a windows service In general, we should create a Windows Service to run code in the background all the time, without any sort of user interaction. An asp.net developer can use a windows service to host a wcf service. We can then configure the windows service to start automatically when the computer starts. This makes our WCF service always available for clients to consume, even if no-one is logged on, on that computer. In our next video, we will discuss, creating a windows service to host a WCF service
Views: 78949 kudvenkat
sql server dirty read example
 
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Text version of the video http://csharp-video-tutorials.blogspot.com/2015/08/sql-server-dirty-read-example.html Slides http://csharp-video-tutorials.blogspot.com/2015/08/sql-server-dirty-read-example_15.html All SQL Server Text Articles http://csharp-video-tutorials.blogspot.com/p/free-sql-server-video-tutorials-for.html All SQL Server Slides http://csharp-video-tutorials.blogspot.com/p/sql-server.html All Dot Net and SQL Server Tutorials in English https://www.youtube.com/user/kudvenkat/playlists?view=1&sort=dd All Dot Net and SQL Server Tutorials in Arabic https://www.youtube.com/c/KudvenkatArabic/playlists In this video we will discuss, dirty read concurrency problem with an example. This is continuation to Part 70. Please watch Part 70 from SQL Server tutorial for beginners. A dirty read happens when one transaction is permitted to read data that has been modified by another transaction that has not yet been committed. In most cases this would not cause a problem. However, if the first transaction is rolled back after the second reads the data, the second transaction has dirty data that does not exist anymore. SQL script to create table tblInventory Create table tblInventory ( Id int identity primary key, Product nvarchar(100), ItemsInStock int ) Go Insert into tblInventory values ('iPhone', 10) Dirty Read Example : In the example below, Transaction 1, updates the value of ItemsInStock to 9. Then it starts to bill the customer. While Transaction 1 is still in progress, Transaction 2 starts and reads ItemsInStock value which is 9 at the moment. At this point, Transaction 1 fails because of insufficient funds and is rolled back. The ItemsInStock is reverted to the original value of 10, but Transaction 2 is working with a different value (i.e 10). Transaction 1 : Begin Tran Update tblInventory set ItemsInStock = 9 where Id=1 -- Billing the customer Waitfor Delay '00:00:15' -- Insufficient Funds. Rollback transaction Rollback Transaction Transaction 2 : Set Transaction Isolation Level Read Uncommitted Select * from tblInventory where Id=1 Read Uncommitted transaction isolation level is the only isolation level that has dirty read side effect. This is the least restrictive of all the isolation levels. When this transaction isolation level is set, it is possible to read uncommitted or dirty data. Another option to read dirty data is by using NOLOCK table hint. The query below is equivalent to the query in Transaction 2. Select * from tblInventory (NOLOCK) where Id=1
Views: 70495 kudvenkat
Part 1   How to find nth highest salary in sql
 
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Link for all dot net and sql server video tutorial playlists http://www.youtube.com/user/kudvenkat/playlists Link for slides, code samples and text version of the video http://csharp-video-tutorials.blogspot.com/2014/05/part-1-how-to-find-nth-highest-salary_17.html This is a very common SQL Server Interview Question. There are several ways of finding the nth highest salary. By the end of this video, we will be able to answer all the following questions as well. How to find nth highest salary in SQL Server using a Sub-Query How to find nth highest salary in SQL Server using a CTE How to find the 2nd, 3rd or 15th highest salary Let's use the following Employees table for this demo Use the following script to create Employees table Create table Employees ( ID int primary key identity, FirstName nvarchar(50), LastName nvarchar(50), Gender nvarchar(50), Salary int ) GO Insert into Employees values ('Ben', 'Hoskins', 'Male', 70000) Insert into Employees values ('Mark', 'Hastings', 'Male', 60000) Insert into Employees values ('Steve', 'Pound', 'Male', 45000) Insert into Employees values ('Ben', 'Hoskins', 'Male', 70000) Insert into Employees values ('Philip', 'Hastings', 'Male', 45000) Insert into Employees values ('Mary', 'Lambeth', 'Female', 30000) Insert into Employees values ('Valarie', 'Vikings', 'Female', 35000) Insert into Employees values ('John', 'Stanmore', 'Male', 80000) GO To find the highest salary it is straight forward. We can simply use the Max() function as shown below. Select Max(Salary) from Employees To get the second highest salary use a sub query along with Max() function as shown below. Select Max(Salary) from Employees where Salary [ (Select Max(Salary) from Employees) To find nth highest salary using Sub-Query SELECT TOP 1 SALARY FROM ( SELECT DISTINCT TOP N SALARY FROM EMPLOYEES ORDER BY SALARY DESC ) RESULT ORDER BY SALARY To find nth highest salary using CTE WITH RESULT AS ( SELECT SALARY, DENSE_RANK() OVER (ORDER BY SALARY DESC) AS DENSERANK FROM EMPLOYEES ) SELECT TOP 1 SALARY FROM RESULT WHERE DENSERANK = N To find 2nd highest salary we can use any of the above queries. Simple replace N with 2. Similarly, to find 3rd highest salary, simple replace N with 3. Please Note: On many of the websites, you may have seen that, the following query can be used to get the nth highest salary. The below query will only work if there are no duplicates. WITH RESULT AS ( SELECT SALARY, ROW_NUMBER() OVER (ORDER BY SALARY DESC) AS ROWNUMBER FROM EMPLOYEES ) SELECT SALARY FROM RESULT WHERE ROWNUMBER = 3
Views: 915586 kudvenkat
Stored procedures in sql server   Part 18
 
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In this video we will learn 1. What is a stored procedure 2. Stored Procedure example 3. Creating a stored procedure with parameters 4. Altering SP 5. Viewing the text of the SP 6. Dropping the SP 7. Encrypting stored procedure Text version of the video http://csharp-video-tutorials.blogspot.com/2012/08/stored-procedures-part-18.html Slides http://csharp-video-tutorials.blogspot.com/2013/08/part-18-stored-procedures.html All SQL Server Text Articles http://csharp-video-tutorials.blogspot.com/p/free-sql-server-video-tutorials-for.html All SQL Server Slides http://csharp-video-tutorials.blogspot.com/p/sql-server.html All Dot Net and SQL Server Tutorials in English https://www.youtube.com/user/kudvenkat/playlists?view=1&sort=dd All Dot Net and SQL Server Tutorials in Arabic https://www.youtube.com/c/KudvenkatArabic/playlists
Views: 742205 kudvenkat
Part 15   Exception handling in WCF
 
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Link for code samples used in the demo http://csharp-video-tutorials.blogspot.com/2013/12/part-15-exception-handling-in-wcf_5.html Link for all dot net and sql server video tutorial playlists http://www.youtube.com/user/kudvenkat/playlists When an exception occurs in a WCF service, the service serializes the exception into a SOAP fault, and then sends the SOAP fault to the client. By default unhandled exception details are not included in SOAP faults that are propagated to client applications for security reasons. Instead a generic SOAP fault is returned to the client. For debugging purpose, if you want to include exception details in SOAP faults, enable IncludeExceptionDetailInFaults setting. This can be done in 2 ways as shown below. 1. In the config file using service behavior configuration [behaviors] [serviceBehaviors] [behavior name="inculdeExceptionDetails"] [serviceDebug includeExceptionDetailInFaults="true"/] [/behavior] [/serviceBehaviors] [/behaviors] 2. In code using ServiceBehavior attribute [ServiceBehavior(IncludeExceptionDetailInFaults=true)] public class CalculatorService : ICalculatorService { public int Divide(int Numerator, int Denominator) { return Numerator / Denominator; } } Frequently asked WCF interview questions What happens when an exception occurs in a WCF service? OR What is a SOAP fault? OR How are WCF service exceptions reported to client applications?
Views: 73650 kudvenkat
Non repeatable read example in sql server
 
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Text version of the video http://csharp-video-tutorials.blogspot.com/2015/08/non-repeatable-read-example-in-sql.html Slides http://csharp-video-tutorials.blogspot.com/2015/08/non-repeatable-read-example-in-sql_17.html All SQL Server Text Articles http://csharp-video-tutorials.blogspot.com/p/free-sql-server-video-tutorials-for.html All SQL Server Slides http://csharp-video-tutorials.blogspot.com/p/sql-server.html All Dot Net and SQL Server Tutorials in English https://www.youtube.com/user/kudvenkat/playlists?view=1&sort=dd All Dot Net and SQL Server Tutorials in Arabic https://www.youtube.com/c/KudvenkatArabic/playlists In this video we will discuss non repeatable read concurrency problem with an example. Non repeatable read problem happens when one transaction reads the same data twice and another transaction updates that data in between the first and second read of transaction one. Transaction 1 starts first. Reads ItemsInStock. Gets a value of 10 for first read. Transaction 1 is doing some work and at this point Transaction 2 starts and UpdatesItemsInStock to 5. Transaction 1 then makes a second read. At this point Transaction 1 gets a value of 5, reulting in non-repeatable read problem. Non-repeatable read example : Open 2 instances of SQL Server Management studio. From the first window execute Transaction 1 code and from the second window, execute Transaction 2 code. Notice that when Transaction 1 completes, it gets different values for read 1 and read 2, resulting in non-repeatable read. -- Transaction 1 Begin Transaction Select ItemsInStock from tblInventory where Id = 1 -- Do Some work waitfor delay '00:00:10' Select ItemsInStock from tblInventory where Id = 1 Commit Transaction -- Transaction 2 Update tblInventory set ItemsInStock = 5 where Id = 1 Repeatable read or any other higher isolation level should solve the non-repeatable read problem. Fixing non repeatable read concurrency problem : To fix the non-repeatable read problem, set transaction isolation level of Transaction 1 to repeatable read. This will ensure that the data that Transaction 1 has read, will be prevented from being updated or deleted elsewhere. This solves the non-repeatable read problem. When you execute Transaction 1 and 2 from 2 different instances of SQL Server management studio, Transaction 2 is blocked until Transaction 1 completes and at the end of Transaction 1, both the reads get the same value for ItemsInStock. -- Transaction 1 Set transaction isolation level repeatable read Begin Transaction Select ItemsInStock from tblInventory where Id = 1 -- Do Some work waitfor delay '00:00:10' Select ItemsInStock from tblInventory where Id = 1 Commit Transaction -- Transaction 2 Update tblInventory set ItemsInStock = 5 where Id = 1
Views: 51033 kudvenkat
How to get the last generated identity column value in SQL Server - Part 8
 
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In this video we will learn 1. Retrieve the last generated identity column value 2. Difference between SCOPE_IDENTITY(), @@Identity and IDENT_CURRENT('TableName') Text version of the video http://csharp-video-tutorials.blogspot.com/2012/08/how-to-get-last-generated-identity.html Slides http://csharp-video-tutorials.blogspot.com/2013/08/part-8-retrieving-identity-column-values.html All SQL Server Text Articles http://csharp-video-tutorials.blogspot.com/p/free-sql-server-video-tutorials-for.html All SQL Server Slides http://csharp-video-tutorials.blogspot.com/p/sql-server.html All Dot Net and SQL Server Tutorials in English https://www.youtube.com/user/kudvenkat/playlists?view=1&sort=dd All Dot Net and SQL Server Tutorials in Arabic https://www.youtube.com/c/KudvenkatArabic/playlists
Views: 324626 kudvenkat
Angular component lifecycle hooks
 
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Text version of the video http://csharp-video-tutorials.blogspot.com/2017/08/angular-component-lifecycle-hooks.html Slides http://csharp-video-tutorials.blogspot.com/2017/08/angular-component-lifecycle-hooks_1.html Angular 2 Tutorial playlist https://www.youtube.com/playlist?list=PL6n9fhu94yhWqGD8BuKuX-VTKqlNBj-m6 Angular 2 Text articles and slides http://csharp-video-tutorials.blogspot.com/2017/06/angular-2-tutorial-for-beginners_12.html All Dot Net and SQL Server Tutorials in English https://www.youtube.com/user/kudvenkat/playlists?view=1&sort=dd All Dot Net and SQL Server Tutorials in Arabic https://www.youtube.com/c/KudvenkatArabic/playlists In this video we will discuss Angular component lifecycle hooks. A component has a lifecycle managed by Angular. Angular 1. Creates the component 2. Renders the component 3. Creates and renders the component children 4. Checks when the component data-bound properties change, and 5. Destroys the component before removing it from the DOM To tap into and react when these life cycle events occur, angular offers several lifecycle hooks The 3 most commonly used hooks are ngOnChanges - Executes, every time the value of an input property changes. The hook method receives a SimpleChanges object containing current and previous property values. This is called before ngOnInit. ngOnInit - Executes after the constructor and after ngOnChange hook for the first time. It is most commonly used for component initialisation and retrieving data from a database. ngOnDestroy - Executes just before angular destroys the component and generally used for performing cleanup. There are 3 simple steps to use the Life Cycle Hooks Step 1 : Import the Life Cycle Hook interface. For example, to use ngOnInit() life cycle hook, import OnInit interface. import { OnInit } from '@angular/core'; Step 2 : Make the component class implement the Life Cycle Hook interface, using the implements keyword as shown below. This step is optional, but good to have so you will get editor support and flags errors at compile time if you incorrectly implement the interface method or make any typographical errors. export class SimpleComponent implements OnInit { } Step 3 : Write the implementation code for the life cycle interface method. Each interface has a single hook method whose name is the interface name prefixed with ng. ngOnInit() { console.log('OnInit Life Cycle Hook'); } Let's understand ngOnChanges life cycle hook with a simple example. Here is what we want to do. As soon as the user starts typing into the text box, we want to capture the current and previous value and log it to the browser console. We can very easily achieve this by using the ngOnChanges life cycle hook. ngOnChanges, is called every time the value of an input property of a component changes. So first let's create a SimpleComponent with an input property as shown below. We will continue with the example we worked with in our previous video. Add a new folder in the App folder and name it Others. Add a new TypeScript file to this folder and name it - simple.component.ts. Copy and paste the following code which is commented and self explanatory. // Step 1 : Import OnChanges and SimpleChanges import { Component, Input, OnChanges, SimpleChanges } from '@angular/core'; // The selector "simple" will be used as the directive // where we want to use this component. Notice we are // also using the simpleInput property with interpolation // to display the value it receives from the parent // component @Component({ selector: 'simple', template: `You entered : {{simpleInput}}` }) // Step 2 : Implement OnChanges Life Cycle Hook interface export class SimpleComponent implements OnChanges { // Input property. As and when this property changes // ngOnChanges life cycle hook method is called @Input() simpleInput: string; // Step 3 : Implementation for the hook method // This code logs the current and previous value // to the console. ngOnChanges(changes: SimpleChanges) { for (let propertyName in changes) { let change = changes[propertyName]; let current = JSON.stringify(change.currentValue); let previous = JSON.stringify(change.previousValue); console.log(propertyName + ': currentValue = ' + current + ', previousValue = ' + previous); // The above line can be rewritten using // placeholder syntax as shown below // console.log(`${propertyName}: currentValue // = ${current }, previousValue = ${previous }`); } } }
Views: 91030 kudvenkat
Part 72   HandleError attribute in mvc
 
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Link for code samples used in the demo http://csharp-video-tutorials.blogspot.com/2013/08/part-72-handleerror-attribute-in-mvc.html Link for csharp, asp.net, ado.net, dotnet basics, mvc and sql server video tutorial playlists http://www.youtube.com/user/kudvenkat/playlists In this video, we will discuss HandleError attribute in asp.net mvc. HandleErrorAttribute is used to display friendly error pages to end user when there is an unhandled exception. Let us understand this with an example. Step 1: Create a blank asp.net mvc 4 application. Step 2: Add a HomeController. Copy and paste the following code. public ActionResult Index() { throw new Exception("Something went wrong"); } Notice that, the Index() action method throws an exception. As this exception is not handled, when you run the application, you will get the default "yellow screen of death" which does not make sense to the end user. Now, let us understand replacing this yellow screen of death, with a friendly error page. Step 3: Enable custom errors in web.config file, that is present in the root directory of your mvc application. "customErrors" element must be nested under "[system.web]" [customErrors mode="On"] [/customErrors] Step 4: Add "Shared" folder under "Views" folder. Add Error.cshtml view inside this folder. Paste the following HTML in Error.cdhtml view. [h2]An unknown problem has occured, please contact Admin[/h2] Run the application, and notice that, you are redirected to the friendly "Error" view, instead of the generic "Yellow screen of death". We did not apply HandleError attribute anywhere. So how did all this work? HandleErrorAttribute is added to the GlobalFilters collection in global.asax. When a filter is added to the GlobalFilters collection, then it is applicable for all controllers and their action methods in the entire application. Right click on "RegisterGlobalFilters()" method in Global.asax, and select "Go To Definition" and you can find the code that adds "HandleErrorAttribute" to GlobalFilterCollection. public static void RegisterGlobalFilters(GlobalFilterCollection filters) { filters.Add(new HandleErrorAttribute()); } Is the friendly error page displayed for HTTP status code 404? No, but there is a way to display the friendly error page. In the HomeController, we do not have List() action method. So, if a user navigates to /Home/List, we get an error - The resource cannot be found. HTTP 404. To display a friendly error page in this case Step 1: Add "ErrorController" to controllers folder. Copy and paste the following code. public class ErrorController : Controller { public ActionResult NotFound() { return View(); } } Step 2: Right click on "Shared" folder and add "NotFound.cshtml" view. Copy and paste the following code. [h2]Please check the URL. The page you are looking for cannot be found[/h2] Step 3: Change "customErrors" element in web.config as shown below. [customErrors mode="On"] [error statusCode="404" redirect="~/Error/NotFound"/] [/customErrors] Make sure to replace [ with LESSTHAN and ] with GREATERTHAN symbol.
Views: 101858 kudvenkat
Part 60 C# Tutorial Difference between String and StringBuilder
 
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Tags string stringbuilder performance system.text.stringbuilder performance advantage of using system.text.stringbuilder over system.string stringbuilder namespace in c# stringbuilder append method c# stringbuilder append function convert stringbuilder object to string when to use stringbuilder over string stringbuilder vs string concatenation c# performance c# string concatenation best practice c# stringbuilder vs string concatenation string manipulation c# In this video we will understand the difference between System.String and System.Text.StringBuilder classes. We will also understand the difference between the terms mutable and immutable strings. C#, SQL Server, WCF, MVC and ASP .NET video tutorials for beginners https://www.youtube.com/user/kudvenkat/playlists?view=1&sort=dd My Blog: www.csharp-video-tutorials.blogspot.com
Views: 111231 kudvenkat
Deploy angular app to IIS
 
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In this video we will discuss deploying angular application to IIS. Here are the steps Step 1 : Build your angular application. If you want to deploy a development build do a development build using the following Angular CLI command. The base-href option on the build command sets the base-href element in index.html to "/ePortal/" instaed of "/". In the IIS server, we will create an application with name "ePortal" in just a bit. ng build --base-href /ePortal/ If you want to deploy a production build do a production build using the following Angular CLI command. ng build --prod --base-href /ePortal/ In our case let's deploy a production build. After the build is complete, you will notice a folder with name "dist" in your Angular project folder. This folder contains all the build files. These build files need to be copied to a folder on the server where we have IIS installed. Step 2 : Create a folder on the server where you have IIS installed. You can name the folder anything you want. I am going to name the folder "ProductionBuild" and I am creating it in C:\ drive. Step 3 : Now copy all the contents of the "dist" folder into "ProductionBuild" folder Step 4 : Open IIS. There are several ways to do this. One way is to type "inetmgr" in the "Run" window and click "OK" Step 5 : Create an application in IIS. Name it "ePortal". This name has to match the value we have specified for the --base-href option in Step 1. a) Exapand the root IIS node b) Expand Sites c) Right click on "Default Web Site" and select "Add Application" from the context menu d) In the "Alias" textbox, type "ePortal" e) Set the "Physical Path" to folder that contains the build files. In our case it is "ProductionBuild" folder in C:\ drive At this point, if you launch the browser and navigate to http://localhost/ePortal/home, you will see the "home works" message as expected. When you click on the "Employees" tab it also works as expected. However, when you "Refresh" the page by pressing F5, you will see HTTP 404 error Step 6 : To fix this Page Refresh issue in Angular, include the following URL rewrite rule in you web.config file. This web.config file should be in copied the "ProductionBuild" folder where we have the rest of the build files. Please replace [ with LESS_THAN symbol and ] with GREATER_THAN symbol. [?xml version="1.0" encoding="utf-8"?] [configuration] [system.webServer] [rewrite] [rules] [rule name="AngularJS Routes" stopProcessing="true"] [match url=".*" /] [conditions logicalGrouping="MatchAll"] [add input="{REQUEST_FILENAME}" matchType="IsFile" negate="true" /] [add input="{REQUEST_FILENAME}" matchType="IsDirectory" negate="true" /] [add input="{REQUEST_URI}" pattern="^/(api)" negate="true" /] [/conditions] [action type="Rewrite" url="/ePortal" /] [/rule] [/rules] [/rewrite] [/system.webServer] [/configuration] Please note : You may also point the IIS application directly to the "dist" folder in RoutingDemo project folder. The downside of this is every time you rebuild your application, the "dist" folder is deleted and recreated. This means you will loose the web.config file and you have to create it again. Text version of the video http://csharp-video-tutorials.blogspot.com/2017/11/deploy-angular-app-to-iis.html Slides http://csharp-video-tutorials.blogspot.com/2017/11/deploy-angular-app-to-iis-slides.html Angular CLI Tutorial https://www.youtube.com/watch?v=rJ9o4TyhSuo&list=PL6n9fhu94yhWUcq5Pc16uf8YKXoZ87Vh_ Angular CLI Text articles & Slides http://csharp-video-tutorials.blogspot.com/2017/10/angular-cli-tutorial-for-beginners.html All Dot Net and SQL Server Tutorials in English https://www.youtube.com/user/kudvenkat/playlists?view=1&sort=dd All Dot Net and SQL Server Tutorials in Arabic https://www.youtube.com/c/KudvenkatArabic/playlists
Views: 41774 kudvenkat
Async and await in C# example
 
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In this video we will discuss async and await keywords and their use with an example. Text version of the video http://csharp-video-tutorials.blogspot.com/2016/10/async-and-await-in-c-example.html Slides http://csharp-video-tutorials.blogspot.com/2016/10/async-and-await-in-c-example_31.html All C# Text Articles http://csharp-video-tutorials.blogspot.com/p/free-c-video-tutorial-for-beginners.html All C# Slides http://csharp-video-tutorials.blogspot.com/p/c.html All C# Videos https://www.youtube.com/playlist?list=PLAC325451207E3105 All Dot Net and SQL Server Tutorials in English https://www.youtube.com/user/kudvenkat/playlists?view=1&sort=dd All Dot Net and SQL Server Tutorials in Arabic https://www.youtube.com/c/KudvenkatArabic/playlists
Views: 191897 kudvenkat
FromBody and FromUri in Web API
 
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Text version of the video http://csharp-video-tutorials.blogspot.com/2016/09/frombody-and-fromuri-in-web-api.html Slides http://csharp-video-tutorials.blogspot.com/2016/09/frombody-and-fromuri-in-web-api_19.html All ASP.NET Web API Text Articles and Slides http://csharp-video-tutorials.blogspot.com/2016/09/aspnet-web-api-tutorial-for-beginners.html All ASP.NET Web API Videos https://www.youtube.com/playlist?list=PL6n9fhu94yhW7yoUOGNOfHurUE6bpOO2b All Dot Net and SQL Server Playlists https://www.youtube.com/user/kudvenkat/playlists?view=1&sort=dd
Views: 95230 kudvenkat
Part 31 - C# Tutorial - Explicit interfaces implementation.avi
 
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In this part of the c sharp tutorial we will learn about explicit interface implementation. Text version of the video http://csharp-video-tutorials.blogspot.com/2012/06/part-31-c-tutorial-explicit-interface.html Slides http://csharp-video-tutorials.blogspot.com/2013/08/part-31-explicit-interface.html All C# Text Articles http://csharp-video-tutorials.blogspot.co.uk/p/free-c-video-tutorial-for-beginners.html All C# Slides http://csharp-video-tutorials.blogspot.com/p/c.html Complete C# tutorial https://www.youtube.com/playlist?list=PLAC325451207E3105 All Dot Net and SQL Server Tutorials in English https://www.youtube.com/user/kudvenkat/playlists?view=1&sort=dd All Dot Net and SQL Server Tutorials in Arabic https://www.youtube.com/c/KudvenkatArabic/playlists
Views: 244445 kudvenkat
CTE in sql server   Part 49
 
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In this video we will learn about creating and referencing CTE's in SQL server. We will also learn how to create multiple CTE's using a single WITH clause. Text version of the video http://csharp-video-tutorials.blogspot.com/2012/09/common-table-expressions-part-49.html Slides http://csharp-video-tutorials.blogspot.com/2013/09/part-49-cte.html All SQL Server Text Articles http://csharp-video-tutorials.blogspot.com/p/free-sql-server-video-tutorials-for.html All SQL Server Slides http://csharp-video-tutorials.blogspot.com/p/sql-server.html All Dot Net and SQL Server Tutorials in English https://www.youtube.com/user/kudvenkat/playlists?view=1&sort=dd All Dot Net and SQL Server Tutorials in Arabic https://www.youtube.com/c/KudvenkatArabic/playlists
Views: 186266 kudvenkat
UNPIVOT in SQL Server
 
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sql server convert columns to rows in a table sql server transpose columns to rows unpivot in sql server example sql server unpivot example In this video we will discuss UNPIVOT operator in SQL Server. PIVOT operator turns ROWS into COLUMNS, where as UNPIVOT turns COLUMNS into ROWS. We dicussed PIVOT operator in Part 54 of SQL Server tutorial. Please watch Part 54 before proceeding. http://csharp-video-tutorials.blogspot.com/2012/10/pivot-operator-in-sql-server-part-54.html Let us understand UNPIVOT with an example. We will use the following tblProductSales table in this demo. SQL Script to create tblProductSales table Create Table tblProductSales ( SalesAgent nvarchar(50), India int, US int, UK int ) Go Insert into tblProductSales values ('David', 960, 520, 360) Insert into tblProductSales values ('John', 970, 540, 800) Go Write a query to turn COLUMNS into ROWS. SELECT SalesAgent, Country, SalesAmount FROM tblProductSales UNPIVOT ( SalesAmount FOR Country IN (India, US ,UK) ) AS UnpivotExample Text version of the video http://csharp-video-tutorials.blogspot.com/2015/10/unpivot-in-sql-server.html Slides http://csharp-video-tutorials.blogspot.com/2015/10/unpivot-in-sql-server_10.html All SQL Server Text Articles http://csharp-video-tutorials.blogspot.com/p/free-sql-server-video-tutorials-for.html All SQL Server Slides http://csharp-video-tutorials.blogspot.com/p/sql-server.html All Dot Net and SQL Server Tutorials in English https://www.youtube.com/user/kudvenkat/playlists?view=1&sort=dd All Dot Net and SQL Server Tutorials in Arabic https://www.youtube.com/c/KudvenkatArabic/playlists
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html attribute vs dom property
 
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Text version of the video http://csharp-video-tutorials.blogspot.com/2017/06/html-attribute-vs-dom-property.html Slides http://csharp-video-tutorials.blogspot.com/2017/06/html-attribute-vs-dom-property_20.html Angular 2 Tutorial playlist https://www.youtube.com/playlist?list=PL6n9fhu94yhWqGD8BuKuX-VTKqlNBj-m6 Angular 2 Text articles and slides http://csharp-video-tutorials.blogspot.com/2017/06/angular-2-tutorial-for-beginners_12.html All Dot Net and SQL Server Tutorials in English https://www.youtube.com/user/kudvenkat/playlists?view=1&sort=dd All Dot Net and SQL Server Tutorials in Arabic https://www.youtube.com/c/KudvenkatArabic/playlists In this video we will discuss the difference between HTML attribute and DOM property. What is DOM DOM stands for Document Object Model. When a browser loads a web page, the browser creates a Document Object Model of that page. In simple terms you can think of the DOM as an application programming interface (API) for HTML, and we can use programming languages like JavaScript, or JavaScript frameworks like Angular to access and manipulate the HTML using their corresponding DOM objects. In other words DOM contains the HTML elements as objects, their properties, methods and events and it is a standard for accessing, modifying, adding or deleting HTML elements. In the previous 2 videos we discussed interpolation and property binding in Angular. Interpolation example [button disabled='{{isDisabled}}']Click Me[/button] Property binding example [button [disabled]='isDisabled']Click Me[/button] If you notice the above 2 examples, it looks like we are binding to the Button's disabled attribute. This is not true. We are actually binding to the disabled property of the button object. Angular data-binding is all about binding to DOM object properties and not HTML element attributes. What is the difference between HTML element attribute and DOM property Attributes are defined by HTML, where as properties are defined by the DOM. Attributes initialize DOM properties. Once the initialization complete, the attributes job is done. Property values can change, where as attribute values can't. Let's prove this point - Property values change, but the attribute values don't with an example. In the example below, we have set the value attribute of the input element to Tom. [input id='inputId' type='text' value='Tom'] At this point, run the web page and in the textbox you will see 'Tom' as the value. Launch the browser developer tools. On the 'Console' tab, use the getattribute() method and value property of the input element to get the attribute and property values. Notice at the moment both have the value 'Tom' Change the value in the textbox to Mary. Notice now, when we query for the attribute and property values, the attribute value is still Tom but the property value is Mary. So this proves the point - Property values change, where as attribute values don't. So it is important to keep in mind that, HTML attributes and the DOM properties are different things. Angular binding works with properties and events, and not attributes. The role of attributes is to initialize element properties and their job is done.
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Part 51   Advantages of using strongly typed views
 
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Link for code samples used in the demo http://csharp-video-tutorials.blogspot.com/2013/07/part-51-advantages-of-using-strongly.html Link for csharp, asp.net, ado.net, dotnet basics, mvc and sql server video tutorial playlists http://www.youtube.com/user/kudvenkat/playlists Make sure to replace [ with LESSTHAN and ] with GREATERTHAN symbol. There are several ways available to pass data from a controller to a view in an mvc application. 1. ViewBag or ViewData 2. Dynamic type 3. Strongly typed view The following are the advantages of using strongly typed views. We get 1. Intellisense and 2. Compile-time error checking With ViewBag and Dynamic type, we don't have these advantages. Using ViewBag: Notice that, the employee object is stored in ViewBag. In HomeController.cs public ActionResult Details(int id) { SampleDBContext db = new SampleDBContext(); Employee employee = db.Employees.Single(x =] x.Id == id); ViewBag.EmployeeData = employee; return View(); } We want to display employee FullName and Gender. Notice that, as we are typing FullName and Gender properties, we don't get intellisense. Also, if we mis-spell FullName or Gender properties, we will not get any compilation errors. We will come to know about these errors only at runtime. In Details.cshtml View [div class="display-label"] @Html.DisplayName("FullName") [/div] [div class="display-field"] @ViewBag.EmployeeData.FullName [/div] [div class="display-label"] @Html.DisplayName("Gender") [/div] [div class="display-field"] @ViewBag.EmployeeData.Gender [/div] Using Dynamic Type: In HomeController.cs public ActionResult Details(int id) { SampleDBContext db = new SampleDBContext(); Employee employee = db.Employees.Single(x =] x.Id == id); return View(employee); } In Details.cshtml View @model dynamic [div class="display-label"] @Html.DisplayName("FullName") [/div] [div class="display-field"] @Model.FullName [/div] [div class="display-label"] @Html.DisplayName("Gender") [/div] [div class="display-field"] @Model.Gender [/div] With dynamic type also, we don't get intellisense and compile-time error checking. Using Strongly Typed View: No change is required in the controller action method. Make the following change to Details.cshtml view. Notice that the view is strongly typed against Employee model class. We get intellisense and if we mis-spell a property name, we get to know about it at compile time. @model MVCDemo.Models.Employee [div class="display-label"] @Html.DisplayName("FullName") [/div] [div class="display-field"] @Model.FullName [div] [div class="display-label"] @Html.DisplayName("Gender") [/div] [div class="display-field"] @Model.Gender [/div] Please Note: We discussed enabling compile time error checking in views in Part 50 of the MVC tutorial.
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Part 36   Instancing modes in WCF
 
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Link for code samples used in the demo http://csharp-video-tutorials.blogspot.com/2014/02/part-36-instancing-modes-in-wcf_25.html Link for all dot net and sql server video tutorial playlists http://www.youtube.com/user/kudvenkat/playlists In this video we will discuss, different instancing modes available in WCF. Instancing modes are also called as instance context modes. Instance context mode dictates, how long the service instance remains on the server. There are 3 instancing modes 1. PerCall - A new instance of service object is created for every request, irrespective of whether the request comes from the same client or a different client. 2. PerSession - A new instance of the service object is created for each new client session and maintained for the duration of that session. 3. Single - A single instance of the service object is created and handles all requests for the lifetime of the application, irrespective of whether the request comes from the same client or a different client. How do you specify what instancing mode you want to use? Use ServiceBehavior attribute and specify InstanceContextMode. In our next video, we will discuss each instancing option and their implications with an example.
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