php中实现数组生成要执行的sql语句

/**
   * [array_to_sql 根据数组key和value拼接成需要的sql]
   * @param [type] $array  [key, value结构数组]
   * @param string $type  [sql类型insert,update]
   * @param array $exclude [排除的字段]
   * @return [string]     [返回拼接好的sql]
   */
  function array_to_sql($array, $type='insert', $exclude = array()){
    
    $sql = '';
    if(count($array) > 0){
      foreach ($exclude as $exkey) {
        unset($array[$exkey]);//剔除不要的key
      }

      if('insert' == $type){
        $keys = array_keys($array);
        $values = array_values($array);
        $col = implode("`, `", $keys);
        $val = implode("', '", $values);
        $sql = "(`$col`) values('$val')";
      }else if('update' == $type){
        $tempsql = '';
        $temparr = array();
        foreach ($array as $key => $value) {
          $tempsql = "'$key' = '$value'";
          $temparr[] = $tempsql;
        }

        $sql = implode(",", $temparr);
      }
    }
    return $sql;
  }