Entity Framework 6 Refresher: Initial Setup

It has been a long time since I used Entity Framework on anything other than an brownfield project where most work consisted of adding or removing the occasional field. This series of posts is intented as a refresher as I relearn some concepts.

1. Initial Setup
2. Seed Data
3. Mapping Files
4. One-to-many mapping
5. Many-to-many mapping
6. Many-to-many self mapping
7. One-to-one mapping

Initial setup.

In a new .Net Framwork class library, add a reference to Microsoft.EntityFramework via the NuGet package manager.

Next add a basic class

public class Person
{
    public int PersonId { get; set; }
    public string FirstName { get; set; }
    public string LastName { get; set; }
}

Then add a DbContext.

public class LearnMappingsContext : DbContext
{
    public DbSet<Person> People { get; set; }
}

Next add a connection string to the app.config file that was created when you added the NuGet package.

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <configSections>
    <!-- For more information on Entity Framework configuration, visit http://go.microsoft.com/fwlink/?LinkID=237468 -->
    <section name="entityFramework" type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" />
  </configSections>
  <connectionStrings>
    <add name="LearnMappings" connectionString="Server=.\SQLEXPRESS;Database=LearnMappings;Trusted_Connection=True;" providerName="System.Data.EntityClient" />
  </connectionStrings>
  <entityFramework>
    <defaultConnectionFactory type="System.Data.Entity.Infrastructure.SqlConnectionFactory, EntityFramework" />
    <providers>
      <provider invariantName="System.Data.SqlClient" type="System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer" />
    </providers>
  </entityFramework>
</configuration>

We are now ready to set up migrations. The first step is to enable them. In the Package Manager Console (PMC from now on - this can be found under Tools | NuGet Package Manager | Package Manager Console) run the command to add migrations:

enable-migrations

This will create a /Migrations folder with a file called configurations.cs.

Next, create the migration for the person class (this does not need to be named “InitialMigration”)

add-migration "InitialMigration"

This will generate a migration script to add the Person class.

Finally, run update-database in the PMC to create the table in your database.