php实现Mysql简易操作类

自己封装的Mysql简易操作类，已塞在Ben框架中，基于PDO来写的，代码风格上有些无厘头。。。
mysql.class.php
<?phpclass mysql extends PDO{public $server;public $database;public $user;public $password;public $sql;public function __construct（$server,$database,$user,$password,$port=3306）{$this->server = $server;$this->database = $database;$this->user = $user;$this->password = $password;parent::__construct（"mysql:host=$server;port=$port;dbname=$database",$user,$password）;$this->query（"SET NAMES utf8"）;}public function drop（$table）{$sql = "DROP TABLE ".$table.";";$re = $this->query（$sql）;if（$re）{return true;}else{return false;}}public function insert（$table,$name,$value=null）{$sql = "INSERT INTO ".$table."（";if（$value == null）{$arrname = array_keys（$name）;$arrvalue = array_values（$name）;}else{$arrname = explode（"|", $name）;$arrvalue = explode（"|", $value）;}for（$i=0;$i<count（$arrname）;$i++）{if（$i==count（$arrname）-1）{$sql = $sql.$arrname[$i];}else{$sql = $sql.$arrname[$i].",";}}$sql = $sql."）VALUES（";for（$i=0;$i<count（$arrvalue）;$i++）{if（$i==count（$arrvalue）-1）{$sql = $sql.""".$arrvalue[$i].""";}else{$sql = $sql.""".$arrvalue[$i]."",";}}$sql .="）;";$re = $this->query（$sql）;if（$re）{return true;}else{return false;}}public function delete（$table,$Conditionsname,$Conditionsvalue=null）{if（$Conditionsvalue！=null）{$sql = "DELETE FROM ".$table." WHERE ".$Conditionsname."="".$Conditionsvalue."";";}else{$sql = "DELETE FROM ".$table." WHERE ";$arrname = array_keys（$Conditionsname）;$arrvalue = array_values（$Conditionsname）;for（$i=0;$i<count（$arrname）;$i++）{if（$i==count（$arrname）-1）{$sql.=$arrname[$i]."=".""".$arrvalue[$i].""";}else{$sql.=$arrname[$i]."=".""".$arrvalue[$i]."",";}}$sql.=";";}$re = $this->query（$sql）;if（$re）{return true;}else{return false;}}public function select（$table,$name,$Conditionsname,$Conditionsvalue=null）{if（$Conditionsvalue！=null）{$sql = "SELECT ".$name." FROM ".$table." WHERE ".$Conditionsname."="".$Conditionsvalue."";";}else{$sql = "SELECT ".$name." FROM ".$table." WHERE ";$arrname = array_keys（$Conditionsname）;$arrvalue = array_values（$Conditionsname）;for（$i=0;$i<count（$arrname）;$i++）{if（$i==count（$arrname）-1）{$sql.=$arrname[$i]."=".""".$arrvalue[$i].""";}else{$sql.=$arrname[$i]."=".""".$arrvalue[$i]."" and ";}}$sql.=";";}$re = $this->query（$sql）;$row = $re->fetch（）;return $row[$name];}public function update（$table,$name,$value,$Conditionsname,$Conditionsvalue=null）{if（$Conditionsvalue！=null）{$sql = "UPDATE ".$table." SET ".$name."= "".$value."" WHERE ".$Conditionsname."="".$Conditionsvalue."";";}else{$sql = "UPDATE ".$table." SET ".$name."= "".$value."" WHERE ";$arrname = array_keys（$Conditionsname）;$arrvalue = array_values（$Conditionsname）;for（$i=0;$i<count（$arrname）;$i++）{if（$i==count（$arrname）-1）{$sql.=$arrname[$i]."=".""".$arrvalue[$i].""";}else{$sql.=$arrname[$i]."=".""".$arrvalue[$i]."" and ";}}$sql.=";";}$re = $this->query（$sql）;if（$re）{return true;}else{return false;}}public function group（$table,$name）{$sql = "SELECT ".$name." FROM ".$table.";";$return = array（）;$re = $this->query（$sql）;while（$row = $re->fetch（PDO::FETCH_ASSOC））{array_push（$return,$row[$name]）;}return $return;}public function fetchall（$sql）{$return = array（）;$re = $this->query（$sql）;while（$row = $re->fetch（PDO::FETCH_ASSOC））{array_push（$return,$row）;}return $return;}}