Estratégias de implantação de banco de dados (SQL Server)

[Migration(62)]
public class _62_add_date_created_column : Migration
{
    public void Up()
    {
       //add it nullable
       Database.AddColumn("Customers", new Column("DateCreated", DateTime) );

       //seed it with data
       Database.Execute("update Customers set DateCreated = getdate()");

       //add not-null constraint
       Database.AddNotNullConstraint("Customers", "DateCreated");
    }

    public void Down()
    {
       Database.RemoveColumn("Customers", "DateCreated");
    }
}