public function init()
    {
        $this->renameTableQueries = array();
        $this->dropCheckQueries = array();
        $this->dropForeignKeyQueries = array();
        $this->dropIndexQueries = array();
        $this->dropPrimaryKeyQueries = array();
        $this->dropColumnQueries = array();
        $this->alterColumnQueries = array();
        $this->createColumnQueries = array();
        $this->createPrimaryKeyQueries = array();
        $this->createIndexQueries = array();
        $this->createForeignKeyQueries = array();
        $this->createCheckQueries = array();
    }