PHP encapsulates a complete instance of mysql class based on singleton mode

The example in this article describes how PHP encapsulates the MySQL class based on the singleton mode. Share it with everyone for your reference, the details are as follows:

Class:

<?php
header("content-type:text/html;charset=utf-8");
//封装一个类
/*
掌握满足单例模式的必要条件
(1)私有的构造方法-为了防止在类外使用new关键字实例化对象
(2)私有的成员属性-为了防止在类外引入这个存放对象的属性
(3)私有的克隆方法-为了防止在类外通过clone成生另一个对象
(4)公有的静态方法-为了让用户进行实例化对象的操作
*/
class db{
  //三私一共
  //私有的静态属性
  private static $dbcon=false;
  //私有的构造方法
  private function __construct(){
  $dbcon=@mysql_connect("localhost","root","root");
   mysql_select_db("small2",$dbcon) or die("mysql_connect error");
   mysql_query("set names utf8");
  }
  //私有的克隆方法
  private function __clone(){}
  //公用的静态方法
  public static function getIntance(){
   if(self::$dbcon==false){
    self::$dbcon=new self;
   }
   return self::$dbcon;
  }
  //打印数据
  public function p($arr){
    echo "<pre class="brush:php;toolbar:false">";
    print_r($arr);
    echo "

"; } public function v($arr){ echo "

";
    var_dump($arr);
    echo "

"; } //执行语句 public function query($sql){ $query=mysql_query($sql); return $query; } /** * 查询某个字段 * @param * @return string or int */ public function getOne($sql){ $query=$this->query($sql); return mysql_result($query,0); } //获取一行记录,return array 一维数组 public function getRow($sql,$type="assoc"){ $query=$this->query($sql); if(!in_array($type,array("assoc",'array',"row"))){ die("mysql_query error"); } $funcname="mysql_fetch_".$type; return $funcname($query); } //获取一条记录,前置条件通过资源获取一条记录 public function getFormSource($query,$type="assoc"){ if(!in_array($type,array("assoc","array","row"))) { die("mysql_query error"); } $funcname="mysql_fetch_".$type; return $funcname($query); } //获取多条数据，二维数组 public function getAll($sql){ $query=$this->query($sql); $list=array(); while ($r=$this->getFormSource($query)) { $list[]=$r; } return $list; } //获得最后一条记录id public function getInsertid(){ return mysql_insert_id(); } /** * 定义添加数据的方法 * @param string $table 表名 * @param string orarray $data [数据] * @return int 最新添加的id */ public function insert($table,$data){ //遍历数组，得到每一个字段和字段的值 $key_str=''; $v_str=''; foreach($data as $key=>$v){ if(empty($v)){ die("error"); } //$key的值是每一个字段s一个字段所对应的值 $key_str.=$key.','; $v_str.="'$v',"; } $key_str=trim($key_str,','); $v_str=trim($v_str,','); //判断数据是否为空 $sql="insert into $table ($key_str) values ($v_str)"; $this->query($sql); //返回上一次增加操做产生ID值 return mysql_insert_id(); } /* * 删除一条数据方法 * @param1 $table, $where=array('id'=>'1') 表名 条件 * @return 受影响的行数 */ public function deleteOne($table, $where){ if(is_array($where)){ foreach ($where as $key => $val) { $condition = $key.'='.$val; } } else { $condition = $where; } $sql = "delete from $table where $condition"; $this->query($sql); //返回受影响的行数 return mysql_affected_rows(); } /* * 删除多条数据方法 * @param1 $table, $where 表名 条件 * @return 受影响的行数 */ public function deleteAll($table, $where){ if(is_array($where)){ foreach ($where as $key => $val) { if(is_array($val)){ $condition = $key.' in ('.implode(',', $val) .')'; } else { $condition = $key. '=' .$val; } } } else { $condition = $where; } $sql = "delete from $table where $condition"; $this->query($sql); //返回受影响的行数 return mysql_affected_rows(); } /** * [修改操作description] * @param [type] $table [表名] * @param [type] $data [数据] * @param [type] $where [条件] * @return [type] */ public function update($table,$data,$where){ //遍历数组，得到每一个字段和字段的值 $str=''; foreach($data as $key=>$v){ $str.="$key='$v',"; } $str=rtrim($str,','); //修改SQL语句 $sql="update $table set $str where $where"; $this->query($sql); //返回受影响的行数 return mysql_affected_rows(); } } ?>

Test:

//mysql测试
//$db=db::getIntance();
//var_dump($db);
/*$sql="select * from acticle";
$list=$db->getAll($sql);
$db->p($list);*/
/*$sql="select * from acticle where acticle_id=95";
$list=$db->getRow($sql);
$db->p($list);
*/
/*$sql="select title from acticle";
$list=$db->getOne($sql);
$db->p($list);*/
//$list=$db->insert("users",$_POST);
//$del=$db->deleteOne("users","id=26");
//$del=$db->deleteAll("users","id in(23,24)");
//$up=$db->update("users",$_POST,"id=27");
//$id=$db->getInsertid();
//print_R($id);

I hope this article will be helpful to everyone in PHP programming.

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