How can you check the existence of tables and indexes in migration before creating them?

Question

Yii

For example, up is creating several tables with indexes. The part fulfills, and then falls out by mistake. Down not done, because the migration did not complete completely and was not included in the table. You have to climb into the database and roll back everything manually.
Is it possible to make checks to skip on up what has already been created?

Answer 1

Why don't you want to wrap everything in a transaction?
Existence checks can be done like this

const DB_TABLE = '{{%product}}';
 public function up()
    {
        if (Yii::$app->db->schema->getTableSchema(self::DB_TABLE, true) === null) {
            $this->createTable(self::DB_TABLE, [
                'id' => 'int(11) NOT NULL AUTO_INCREMENT COMMENT "Идентификатор"',
                 .............................
                'PRIMARY KEY (id)',
            ], 'ENGINE=InnoDB DEFAULT CHARSET=utf8');
        }
    }