PHP基于单例模式实现的数据库操作基类


            本文实例讲述了PHP基于单例模式实现的数据库操作基类。分享给大家供大家参考，具体如下：

配置文件：





<?php

$db = array(

    'host'=>'localhost',

    'user'=>'root',

    'password'=>'',

    'database'=>'test',

)

?>







php 数据库基类：





<?php

class db {

  public $conn;

  public static $sql;

  public static $instance=null;

  private function __construct(){

    require_once('db.config.php');

    $this->conn = mysql_connect($db['host'],$db['user'],$db['password']);

    if(!mysql_select_db($db['database'],$this->conn)){

      echo "失败";

    };

    mysql_query('set names utf8',$this->conn);

  }

  public static function getInstance(){

    if(is_null(self::$instance)){

      self::$instance = new db;

    }

    return self::$instance;

  }

  /**

   * 查询数据库

   */

  public function select($table,$condition=array(),$field = array()){

    $where='';

    if(!empty($condition)){

      foreach($condition as $k=>$v){

        $where.=$k."='".$v."' and ";

      }

      $where='where '.$where .'1=1';

    }

    $fieldstr = '';

    if(!empty($field)){

      foreach($field as $k=>$v){

        $fieldstr.= $v.',';

      }

       $fieldstr = rtrim($fieldstr,',');

    }else{

      $fieldstr = '*';

    }

    self::$sql = "select {$fieldstr} from {$table} {$where}";

    $result=mysql_query(self::$sql,$this->conn);

    $resuleRow = array();

    $i = 0;

    while($row=mysql_fetch_assoc($result)){

      foreach($row as $k=>$v){

        $resuleRow[$i][$k] = $v;

      }

      $i++;

    }

    return $resuleRow;

  }

  /**

   * 添加一条记录

   */

   public function insert($table,$data){

    $values = '';

    $datas = '';

    foreach($data as $k=>$v){

      $values.=$k.',';

      $datas.="'$v'".',';

    }

    $values = rtrim($values,',');

    $datas  = rtrim($datas,',');

    self::$sql = "INSERT INTO {$table} ({$values}) VALUES ({$datas})";

    if(mysql_query(self::$sql)){

      return mysql_insert_id();

    }else{

      return false;

    };

   }

   /**

   * 修改一条记录

   */

  public function update($table,$data,$condition=array()){

    $where='';

    if(!empty($condition)){

      foreach($condition as $k=>$v){

        $where.=$k."='".$v."' and ";

      }

      $where='where '.$where .'1=1';

    }

    $updatastr = '';

    if(!empty($data)){

      foreach($data as $k=>$v){

        $updatastr.= $k."='".$v."',";

      }

      $updatastr = 'set '.rtrim($updatastr,',');

    }

    self::$sql = "update {$table} {$updatastr} {$where}";

    return mysql_query(self::$sql);

  }

  /**

   * 删除记录

   */

   public function delete($table,$condition){

    $where='';

    if(!empty($condition)){

      foreach($condition as $k=>$v){

        $where.=$k."='".$v."' and ";

      }

      $where='where '.$where .'1=1';

    }

    self::$sql = "delete from {$table} {$where}";

    return mysql_query(self::$sql);

   }

  public static function getLastSql(){

    echo self::$sql;

  }

}

$db = db::getInstance();

//$list = $db->select('demo',array('name'=>'tom','password'=>'ds'),array('name','password'));

//echo $db->insert('demo',array('name'=>'中文源码网','password'=>'123'));

//echo $db->update('demo',array("name"=>'xxx',"password"=>'123'),array('id'=>1));

echo $db->delete('demo',array('id'=>'2'));

db::getLastSql();

echo "<pre>";

?>



更多关于PHP操作数据库相关内容感兴趣的读者可查看本站专题：《php+mysql数据库操作入门教程》、《PHP基于pdo操作数据库技巧总结》及《php常见数据库操作技巧汇总》

希望本文所述对大家PHP程序设计有所帮助。