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

    <?php
    class 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;
      }
    }