table = ' '.$table.' ';        return $this;  }/*  设定条件   $where ：array('x>1'=>null,'name'=>'chenglin',...)*/  public function where($where){    $temp = ' WHERE ';    foreach($where as $value => $key){      if($key!=null){        $temp.=$value.'="'.$key.'" AND ';      }else{        $temp.=$value.' AND ';      }         }    $temp = substr($temp,0,-4);    $this->where = $temp;    return $this;  }/*  设定查询字段  ...：以数组的形式接收多个参数  $field:'id,sex'*/  public function field($field){    $temp = '';    $temp .= " {
   $field} ";    $this->field = $temp;    return $this;     }/*  设置查询排序排序方式  $order :'id desc'*/  public function order($order){    $order = ' ORDER BY '.$order.' ';    $this->order = $order;    return $this;  }/*  设置查询结果个数  $limit: 0,3*/  public function limit($limit1,$limit2 = ''){    if($limit2==''){      $limit = ' LIMIT '.$limit1.' ';    }else{      $limit = ' LIMIT '.$limit1.','.$limit2.' ';    }    $this->limit = $limit;    return $this;  }/*  重置变量*/  public function resetting(){    $this->field = ' * ';    $this->table = '';    $this->where = '';    $this->order = '';    $this->limit = '';  }/*  查询一个结果  返回数组*/  public function item(){    $conn = self::db_conn();    $sql = "SELECT{
   $this->field}FROM{
   $this->table}{
   $this->where} LIMIT 1";    if($result = mysqli_query($conn,$sql)){      while($row = mysqli_fetch_assoc($result)){        $rows[]  =  $row;      }      //清空属性      $this->resetting();      return $rows[0];          }  }/*  查询结果集  返回二维数组*/  public function lists($index=''){    $conn = self::db_conn();    $sql = "SELECT{
   $this->field}FROM{
   $this->table}{
   $this->where}{
   $this->order}{
   $this->limit}";    if($result = mysqli_query($conn,$sql)){      while($row = mysqli_fetch_assoc($result)){        $rows[]  =  $row;      }        }            if($index!=''){      $rows = $this->my_index($rows,$index);    }    //清空属性    $this->resetting();     return  $rows;  }/*  插入数据  返回插入的id号插入成功  insert($data):array('name'=>'cl','sex'=>'男')*/  public function insert($data){    $conn = self::db_conn();    $field = $values = [];    foreach($data as $value=>$key){      $field[] = $value;      $values[]  = $key;    }    $sql = "INSERT INTO {
   $this->table} (".implode(',',$field).")VALUES('".implode("','",$values)."')";    $insert_id = 0;    if(mysqli_query($conn,$sql)){      //插入的id      $insert_id = mysqli_insert_id($conn);    }    $this->resetting();     echo $sql;    return $insert_id;  }/*  删除数据  返回1删除成功*/  public function delete(){    //保险,防止全部被更改    if($this->where == ''){      $this->resetting();       return 0;    }    $conn = self::db_conn();    $sql = "DELETE FROM{
   $this->table}{
   $this->where}";    $res = mysqli_query($conn,$sql);    $this->resetting();     return $res;  }/*  更新数据  $data:array('name'=>cl,'age'=>18)  返回1更新成功*/  public function update($data){    //保险,防止全部被更改    if($this->where == ''){      $this->resetting();       return 0;    }    $conn = self::db_conn();    $set = ' SET ';    foreach($data as $value=>$key){      $set.=$value."='".$key."' ,";    }    $set = rtrim($set,',');    $sql = "UPDATE{
   $this->table}{
   $set}{
   $this->where}";    $res = mysqli_query($conn,$sql);    $this->resetting();     return $res;  }/*  自定义索引  $arr:查询到的lists二维数组  $index:$key的键*/  public function my_index($arr,$index){    $new_arr = [];    foreach($arr as $value=>$key){      $new_arr[$key[$index]] = $key;    }    return $new_arr;  }  //查询记录总数  public function count(){    $conn = self::db_conn();    $sql = "SELECT * FROM {
   $this->table}{
   $this->where}";    $count = 0;    if($result = mysqli_query($conn,$sql)){      //查询总条数      $count = mysqli_num_rows($result);    }    $this->resetting();     return $count;    }}          ?>