Database migrations with Entity Framework Core sample app

  • Code Sample
Browse code

This sample demonstrates how to use Entity Framework Core's migrations feature with Aspire.

The sample has three important projects:

  • DatabaseMigrations.ApiService - A web app that calls the database.
  • DatabaseMigrations.MigrationService - A background worker app that applies migrations when it starts up.
  • DatabaseMigrations.ApiModel - The EF Core context, entities, and migrations. This project is used by the API and migration service.

DatabaseMigrations.ApiService and DatabaseMigrations.MigrationService reference a SQL Server resource. During local development the SQL Server resource is launched in a container.

Demonstrates

  • How to create migrations in an Aspire solution
  • How to apply migrations in an Aspire solution

Sample prerequisites

This sample is written in C# and targets .NET 8.0. It requires the .NET 8.0 SDK or later.

Create migration

The DatabaseMigrations.ApiModel project contains the EF Core model and migrations. The dotnet ef command-line tool can be used to create new migrations:

  1. Update the Entry entity in database context in MyDb1Context.cs. Add a Name property:

    public class Entry
{
    public Guid Id { get; set; } = Guid.NewGuid();
    public string? Name { get; set; }
}

  2. Open a command prompt in the DatabaseMigrations.ApiService directory and run the EF Core migration tool to create a migration named MyNewMigration.

    dotnet ef migrations add MyNewMigration --project ..\DatabaseMigrations.ApiModel\DatabaseMigrations.ApiModel.csproj

    The preceding command:

    • Runs EF Core migration command-line tool in the DatabaseMigrations.ApiService directory. dotnet ef is run in this location because the API service is where the DB context is used.
    • Creates a migration named MyNewMigration.
    • Creates the migration in the DatabaseMigrations.ApiModel project.

  3. View the new migration files in the DatabaseMigrations.ApiModel project.

Run the app

If using Visual Studio, open the solution file DatabaseMigrations.sln and launch/debug the DatabaseMigrations.AppHost project.

If using the .NET CLI, run dotnet run from the DatabaseContainers.AppHost directory.

When the app starts up, the DatabaseMigrations.MigrationService background worker runs migrations on the SQL Server container. The migration service:

  • Creates a database in the SQL Server container.
  • Creates the database schema.
  • Stops itself once the migration is complete.