Tried to use Yii migrations to drop one table and to create 2 another. 
Here is code:

```
    <?php

class m130919_095159_create_offer_tables extends CDbMigration
{
    public function up()
    {
        $this->getDbConnection()->createCommand()->dropTable('offer');

        $this->createTable('settings', array(
            'id' => 'pk',
            'offer_id' => 'integer NOT NULL',
            'system_id' => 'integer NULL',  
            'site_title' => 'varchar(255) NULL',
            'index_number' => 'integer NULL',  
            'coupon_token' => 'varchar(255) NULL',
            'facebook_app_id' => 'varchar(255) NULL',
            'facebook_app_secret' => 'varchar(255) NULL',
        ));

        $this->createTable('content', array(
            'id' => 'pk',
            'offer_id' => 'integer NOT NULL',
            'created' => 'datetime NOT NULL',
            'modified' => 'datetime NOT NULL',
            'status' => 'integer NOT NULL',
            'title_uz' => 'varchar(255) NULL',
            'title_ru' => 'varchar(255) NULL',
            'description_uz' => 'text NULL',
            'description_ru' => 'text NULL', 
        ));
    }

    public function down()
    {
        echo "m130919_095159_create_offer_tables does not support migration down.\n";
        return false;
    }
}

```

After i executed command `php yiic.php migrate` and get answer `migrated up successfully`. Problem is sql commands haven't been executed. Table hasen't dropped, another tables doesn't created. No changes in database. Can't find out reason