The Entity Framework Code First approach allows us to create a model as a plain class and then the database gets created from the domain model or entity class. In the Code First approach, the database gets created from the classes.
Some advantages of the Entity Framework Code First approach include (as stated in Scott Gu’s blog):
- Developing without ever having to open a designer or define an XML mapping file
- Defining your model objects by simply writing “plain old classes” with no base classes required
- Using a “convention over configuration” approach that enables database persistence without explicitly configuring anything
- Optionally overriding the convention-based persistence and using a fluent code API to fully customize the persistence mapping
Rather the delving more into theoretical concepts, in this post we will directly jump into code and create a table and database using the Code First approach. In this post we will learn how we can create entities and a relationship between entities in the Entity Framework Code First approach. In the EF Code First approach, there are two options to create the relationship between entities, through:-Data annotations and Fluent API
In this post we will use data annotations to create the relationship between entities.
Create database with one table
Let us start with creating a table named Student in a database with the code first approach. The domain class Student can be created as shown in the listing below:
As you might have already noticed, the Student class is a plain class. Entity Framework will use the Student class to create the table in the database. The Student class represents the domain entity and it should not have any information or references of the database. Entity Framework will use the Student class to create the Student table.
Once the domain entity class is created, next we need to create a Context class which will inherit the DataContext class. The context class can be created as shown in the listing below:
Read the full article on the Infragistics blog
In my trainings, often I get a question from junior developers that how to clone a Git repository in the visual studio? Perhaps it may be very simple for senior developers, however for the developers who struggle to get it right steps are discussed below,
Find the URL of the remote git repository. For GitHub repository URL can be found as shown in the image below. Copy the URL from here.
Launch Visual Studio and from the View select Team Explorer. In the Team Explorer window select Clone.
On clicking Clone, you will get an option to provide the URL of the Git repo and the choose folder in which repository will be cloned. In the URL section paste the remote repository URL as whon in the below image:
As the last step click on the Clone and the remote Git repository will be cloned in the Visual Studio in the given folder. If everything goes right you will get success message as shown below.
I hope it helps. Thanks and Happy Coding.
Have you come across the error as shown in below image?
You get the above shown error in Visual Studio while pulling changes from the git server. This error causes because you have local changes without the commit. In this scenario the visual Studio does not give very readable error message. Perhaps you may want to use git command for pull for more information on the error.
The git pull command clearly says that either commit the changes or stash them. If you are not sure about the local changes then better option is to stash them. Local changes can be stashed using the git stash command.
After stashing the local changes (you can commit also) run the git pull command to pull the remote changes from the git server. You should not get any error doing pulling the latest changes.
Hope it helps. Happy coding.
In this post I will show you to use DebugView to log the Entity Framework. For detail discussion on the same topic you may want to learn more here:
Logging in Entity Framework on Steve Smith Blog
Profiling Database Activity in the Entity Framework by Julie Lerman
Download DebugView , unzip it and Run it as administrator. In Capture menu select the options as shown in below image,
Once the debugview is configured, you should configure the DataContext class as shown below. Enable database log to print on the debug window.
As the last step run the application using Entity framework without using Visual Studio or without attaching Visual Studio Debugger. In Visual Studio run the application using Ctrl+ F5. You should able to view the Entityframework log in Debugview as follows:
The Debugview can be your good friend when you stuck with performance issues and want to log the queries.
While working on an application, I had to commit changes to local Git Repository. It was usual task and I started with following command,
git add –A
To surprise git add command gave me error as shown in image below. Error message was clear that to a particular file there was Permission denied.
Note: I was working on a MVC application which had local database attached. Name of database was MoviesRTM.mdf.
I tried to commit using Visual Studio 2013 as well. Here also I got same error as shown in image below,
This can be solved by two ways either shutting down IIS Express or restarting Visual Studio. I was using IIS Express to host MVC application. You can shut down IIS Express by right click on IIS Express and click on Exit from context menu.
If this option is not working then try restarting Visual Studio.
Note: Restarting Visual Studio or Shutting down IIS Express may worked in this scenario because permission denies error was on a database file (extension mdf). And database was locally created.
After shutting down I was able to run git add command successfully.