Migrations

The EFCore Module integrates seamlessly with Entity Framework Migrations.

Migrations are generated by using the efcore CLI, and are executed automatically by the EFCore Module according to configuration.

Migrations are mostly used to keep the database schema up to date, however they can also be used to seed data. Be careful when using migrations to seed data, since we normally want to keep data separated, either depending on the configured setup or the destination installation.

Using EFCore Migrations

To get started, let's generate some migrations using the EFCore CLI.

Make sure you have the EFCore Module configured with at least an entity.

cd location-of-your-application-project/
dotnet ef migrations add InitialCreate

Tip

Name migrations in PascalCase. They won't pass analyzers if not.

This command will generate a new migration called called InitialCreate that will be added to our project inside the Migrations/ directory. The tool will try to discover a DbContext to find all your entities and to associate the migration to it.

If you have more than one DbContext in the same project, you must specify for which of them you want to add the migration entry. You can do so by adding a --context option to the command being executed, as follows:

dotnet ef migrations add --context SomeDbContext InitialCreate

Migrations with a separate persistence layer

Something worth mentioning is the fact that the DbContext on which you want to add the migration entry, must be discoverable by the tool. The tool will try to build the IHost of your project and try to find a DbContext from the application's dependency injection container. This implies that, if your DbContext is located in another project which doesn't contain a runtime (no host is present), like a Suite Module, the CLI command will fail.

To overcome the previous limitation, you can take advantage of the --startup parameter to specify the project to start the host. The example below shows how to generate migrations when you have your infrastructure layer separated in a different project.

dotnet ef migrations add InitialCreate \
    --startup-project ../Application/UsersApplication.csproj \

When using the microservice template, migrations can be generated by using:

dotnet ef migrations add InitialCreate \
    --startup-project src/services/EquipmentManager/ITsynch.Suite.EquipmentManager.Application \
    --project src/services/EquipmentManager/ITsynch.Suite.EquipmentManager.Persistence.SqlServerProvider/ \
    --output-dir Migrations

Executing migrations

The EFCore Module takes care of executing migrations for you. Currently, they can be executed at two different times.

1. None: migrations won't be executed by the EFCore Module.
2. Lazy: migrations will be try to be executed every time a DbContext needs to be created. Most likely on a per-request/per-message basis.
3. Startup: migrations will be executed during application startup. This is the default and preferred option.

Currently the configuration of migrations is done at the PersistenceModuleOptions and it's limited to configuring the behavior for all DbContexts.

"ITsynch.Suite.App.Modules.PersistenceModuleOptions":
{
    "MigrationsExecutionType": "Lazy"
}