![]() ![]() ![]() enable dotnet ef), how to have a DbContext in separate class library and also how to use migrations even when your DbContext lives in a different project. In this blog post we’ll go through all that, starting with how to manually set up the tooling (i.e. It’s easy to hit speed bumps like not being able to set up the tooling in a console project, or struggling to have a DbContext in separate a classlibrary. Now, we can use the context class to save and retrieve data, as shown below.Setting up Entity Framework in. Now, whenever we add or update domain classes or configurations, we need to sync the database with the model using add-migration and update-database commands. This was the first migration to create a database. It creates a table for each DbSet property ( Students and Courses) as shown below. This will create the database with the name and location specified in the connection string in the UseSqlServer() method. Learn more about it in the Migration chapter.Īfter creating a migration, we still need to create the database using the update-database command in the Package Manager Console, as below.Įnter the following command in dotnet CLI. This will create a new folder named Migrations in the project and create the ModelSnapshot files, as shown below. > dotnet ef migrations add CreateSchoolDB If you use dotnet CLI, enter the following command. In Visual Studio, open NuGet Package Manager Console from Tools -> NuGet Package Manager -> Package Manager Console and enter the following command: We can execute the migration command using NuGet Package Manger Console as well as dotnet CLI (command line interface). So, we need to create the database from the model (entities and context) by adding a migration. The connection string "Server=.\SQLEXPRESS Database=SchoolDB Trusted_Connection=True " in the UseSqlServer method provides database information: Server= specifies the DB Server to use, Database= specifies the name of the database to create and Trusted_Connection=True specifies the Windows authentication mode.ĮF Core will use this connection string to create a database when we run the migration.Īfter creating the context and entity classes, it's time to add the migration to create a database.ĮF Core includes different migration commands to create or update the database based on the model.Īt this point, there is no SchoolDB database. We have installed MS SQL Server provider, which has added the extension method UseSqlServer on DbContextOptionsBuilder. In the OnConfiguring() method, an instance of DbContextOptionsBuilder is used to specify which database to use. OptionsBuilder.UseSqlServer( above context class includes two DbSet properties, for Student and Course, type which will be mapped to the Students and Courses tables in the underlying database. Protected override void OnConfiguring( DbContextOptionsBuilder optionsBuilder) The following SchoolContext class is also called context class. Now, we need to create a context class by deriving the DbContext, as shown in the previous chapter. The followings are simple entity classes for Student and Course: So, we need to create entity classes and context classes first. For example, the storage model will be different for the SQL Server compared with DB2.ĮF uses this model for CRUD (Create, Read, Update, Delete) operations to the underlying database. In the code-first approach, EF builds the conceptual model based on your domain classes (entity classes), the context class and configurations.ĮF Core builds the storage model and mappings based on the provider you use. The EF model includes three parts: conceptual model, storage model, and mapping between the conceptual and storage models. It builds a model based on the shape of your domain classes, the Data Annotations and Fluent API configurations. Creating the ModelĮntity Framework needs to have a model (Entity Data Model) to communicate with the underlying database. Learn more about installing EF Core in the EF Core Installation chapter. ![]() Select on the menu: Tools -> NuGet Package Manager -> Package Manager Console and execute the following command to install the SQL Server provider package: ![]() Now, we need to install EF Core in our console application using Package Manager Console. Enter the Project Name & Location and click the OK button to create a console application, as shown below. In the New Project popup, expand Installed -> Visual C# in the left pane and select the Console App (.NET Core) template in the middle pane. This will open the New Project popup, as shown below. NET Core Console application, open Visual Studio 2017 and select on the menu: File -> New -> Project. NET Core Console application can be created either using Visual Studio 2017 or Command Line Interface (CLI) for. NET Core Console application using Visual Studio 17 (or greater). Here you will learn how to use Entity Framework Core with Code-First approach step by step. ![]()
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