Manually call DbMigration.Up in EF

Question

I want to be able to Up() method of a migration manually. Currently I'm trying to do that but calling that contains CreateTable method does not create the table. I suspect that connection is not properly set. And there are no properties to set it.

I also tried DbMigrator but it calls some internal EF migration methods.

So does anyone know how to set a connection to be used by DbMigration.Up method?

Thanks in advance!

Answer 1

I use the following code to explicitly be able to upgrade my database in the Application_Start event:

var config = new MyDatabaseMigrationsConfiguration();
var migrator = new System.Data.Entity.Migrations.Infrastructure.MigratorLoggingDecorator(new System.Data.Entity.Migrations.DbMigrator(config), new MyCommonMigrationsLogger());
if (migrator.GetPendingMigrations().Any())
{
  migrator.Update();
}

As far as i know this will use the default (named) connectionstring from my DatabaseContext to apply the pending changes.

• You can specify the TargetMigration in the migrator.Update() if you want to be explicit
• The MyCommonMigrationsLogger is just a simple Logging.Common implementation for the System.Data.Entity.Migrations.Infrastructure.MigrationsLogger

Answer 2

For complete manual control over migrations, you can use the following extension method:

public static void RunMigration(this DbContext context, DbMigration migration)
{            
    var prop = migration.GetType().GetProperty("Operations", BindingFlags.NonPublic | BindingFlags.Instance);
    if (prop != null)
    {
        IEnumerable<MigrationOperation> operations = prop.GetValue(migration) as IEnumerable<MigrationOperation>;
        var generator = new SqlServerMigrationSqlGenerator();
        var statements = generator.Generate(operations, "2008");
        foreach (MigrationStatement item in statements)
            context.Database.ExecuteSqlCommand(item.Sql);
    }
}

Example: Having a migration like this:

public class CreateIndexOnContactCodeMigration : DbMigration
{
    public override void Up()
    {
        this.CreateIndex("Contacts", "Code");
    }

    public override void Down()
    {
        base.Down();
        this.DropIndex("Contacts", "Code");
    }
}

You could run it against your DbContext:

using (var dbCrm = new CrmDbContext(connectionString))
{
    var migration = new CreateIndexOnContactCodeMigration();
    migration.Up(); // or migration.Down();                
    dbCrm.RunMigration(migration);
}