<?php

// 数据库连接类

class DB{

  //私有的属性

  private static $dbcon=false;

  private $host;

  private $port;

  private $user;

  private $pass;

  private $db;

  private $charset;

  private $link;

  //私有的构造方法

  private function __construct(){

    $this->host =  'localhost';

    $this->port =  '3306';

    $this->user =  'root';

    $this->pass =  'root';

    $this->db =  'girls';

    $this->charset= 'utf8';

    //连接数据库

    $this->db_connect();

    //选择数据库

    $this->db_usedb();

    //设置字符集

    $this->db_charset();

   }

   //连接数据库

   private function db_connect(){

    $this->link=mysqli_connect($this->host.':'.$this->port,$this->user,$this->pass);

    if(!$this->link){

      echo "数据库连接失败<br>";

      echo "错误编码".mysqli_errno($this->link)."<br>";

      echo "错误信息".mysqli_error($this->link)."<br>";

      exit;

    }

   }

   //设置字符集

    private function db_charset(){

     mysqli_query($this->link,"set names {$this->charset}");

    }

    //选择数据库

   private function db_usedb(){

     mysqli_query($this->link,"use {$this->db}");

   }

   //私有的克隆

   private function __clone(){

     die('clone is not allowed');

   }

   //公用的静态方法

   public static function getIntance(){

     if(self::$dbcon==false){

      self::$dbcon=new self;

     }

     return self::$dbcon;

   }

   //执行sql语句的方法

    public function query($sql){

     $res=mysqli_query($this->link,$sql);

     if(!$res){

      echo "sql语句执行失败<br>";

      echo "错误编码是".mysqli_errno($this->link)."<br>";

      echo "错误信息是".mysqli_error($this->link)."<br>";

     }

     return $res;

   }

    //获得最后一条记录id

    public function getInsertid(){

     return mysqli_insert_id($this->link);

    }

   /**

    * 查询某个字段

    * @param

    * @return string or int

    */

    public function getOne($sql){

     $query=$this->query($sql);

      return mysqli_free_result($query);

    }

    //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("mysqli_query error");

     }

     $funcname="mysqli_fetch_".$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("mysqli_query error");

    }

    $funcname="mysqli_fetch_".$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;

    }

    public function selectAll($table,$where,$fields='*',$order='',$skip=0,$limit=1000)

    {

              if(is_array($where)){

                    foreach ($where as $key => $val) {

                        if (is_numeric($val)) {

                            $condition = $key.'='.$val;

                        }else{

                            $condition = $key.'=\"'.$val.'\"';

                        }

                    }

              } else {

                $condition = $where;

              }

              if (!empty($order)) {

                  $order = " order by ".$order;

              }

              $sql = "select $fields from $table where $condition $order limit $skip,$limit";

              $query = $this->query($sql);

              $list = array();

              while ($r= $this->getFormSource($query)) {

                  $list[] = $r;

              }

              return $list;

    }

     /**

     * 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 $this->getInsertid();

   }

   /*

    * 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 mysqli_affected_rows($this->link);

    }

    /*

    * 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 mysqli_affected_rows($this->link);

    }

   /**

    * [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,$where,$limit=0){

     //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,',');

      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;

      }

        if (!empty($limit)) {

            $limit = " limit ".$limit;

        }else{

            $limit='';

        }

    //修改SQL语句

    $sql="update $table set $str where $condition $limit";

    $this->query($sql);

    //返回受影响的行数

    return mysqli_affected_rows($this->link);

   }

}

?>