protected function _process( array $stmts )
	{
		$this->_msg( 'Changing list ids to NOT NULL', 0 );
		$this->_status('');
		
		foreach( $stmts as $tablename => $stmt )
		{
			$this->_msg(sprintf('Checking table "%1$s": ', $tablename), 1);
			
			if( $this->_schema->tableExists( $tablename ) === true
				&& $this->_schema->getColumnDetails( $tablename, 'id' )->isNullable() === true )
			{
				$this->_execute( $stmt );
				$this->_status( 'migrated' );
			}
			else
			{
				$this->_status( 'OK' );
			}
		}
	}