public function createTable($tableName,$definition,$primaryKey=null,$extra='') {
		$sql="CREATE TABLE `{$tableName}` (";
		foreach($definition as $key=>$type) {
			$sql.="`$key` $type,";
		}
		if ($primaryKey) {
			$sql.=" PRIMARY KEY(`$primaryKey`) ";
		} else {
			$sql=substr($sql,0,-1);
		}
		$sql.="$extra ) ENGINE=MyISAM DEFAULT CHARSET=".$this->charset;
		return $this->runRawQuery($sql,null,true);
	}