<?php
/**
 * Created by JetBrains PhpStorm.
 * User: lee
 * Date: 13-7-26
 * Time: 下午8:30
 * To change this template use File | Settings | File Templates.
 */
class SqlHelper{
  private $mysqli;
  private static $host="localhost";
  private static $user="root";
  private static $pwd="";
  private static $db="world";
  private $sql=false;
  private $result=false;
  function __construct(){
    $this->mysqli=new MySQLi(self::$host,self::$user,self::$pwd,self::$db);
    if($this->mysqli->connect_error){
      die("连接数据库失败！ ".$this->mysql->connect_error);
    }
    $this->mysqli->query("set names utf8");
  }
  function execute_dql_all($sql){
    //执行查询语句
    $arr=array();
    $this->result=$this->mysqli->query($sql) or die ($this->mysql->connect_error);
    //将数据转存到$arr数组中
    while($row=mysqli_fetch_array($this->result,MYSQL_BOTH)){
      $arr[]=$row;
    }
    $this->result->free();
    return $arr;
  }
  function execute_dql_num($sql){
    //执行查询语句
    $arr=array();
    $this->result=$this->mysqli->query($sql) or die ($this->mysql->connect_error);
    //将数据转存到$arr数组中
    while($row=mysqli_fetch_array($this->result,MYSQLI_NUM)){
      $arr[]=$row;
    }
    $this->result->free();
    return $arr;
  }
  function execute_dql_assoc($sql){
    //执行查询语句
    $arr=array();
    $this->result=$this->mysqli->query($sql) or die ($this->mysql->connect_error);
    //将数据转存到$arr数组中
    while($row=mysqli_fetch_array($this->result,MYSQLI_ASSOC)){
      $arr[]=$row;
    }
    $this->result->free();
    return $arr;
  }
  //查询某表中的记录数
  function execute_dql_counts($table,$id="*"){
    $this->sql="select count($id) from $table";
    $this->result=$this->mysqli->query($this->sql);
    $row=mysqli_fetch_all($this->result);
    $this->result->free();
    return $row[0][0];
  }
  function execute_dml($sql){
    //执行正删改
    $this->result=$this->mysqli->query($sql);
    if(!$this->result){
      return -1;//执行正删改失败
    }else{
      if($this->mysqli->affected_rows>0){
        return 1;//执行正删改成功，影响行数
      }else{
        return 0;//执行正删改成功，但没有影响行数
      }
    }
  }
}