aspnet-migration-02.cs

public class AppMigrationEngine: BaseMigrationEngine
{
    public override async Task RunBeforeAsync()
    {
        // Runs before anything else
    }
    
    public override async Task RunBeforeDatabaseMigrationAsync(IDictionary < string, object > cache)
    {
        // Runs before EF Core migrations
        // Use this to capture data before schema changes
        var oldData = await _db.Orders.Select(o => new
        {
            o.Id, o.LegacyStatus
        }).ToListAsync();
        cache["oldStatuses"] = oldData;
    }
    
    public override async Task RunAfterDatabaseMigrationAsync()
    {
        // Runs after EF Core migrations, before application migrations
    }
    
    public override async Task RunAfterAsync()
    {
        // Runs after everything is done
    }
}