php连接数据库类

框架用多啦,别忘记了原生,多练练手 phpmysqli 链接数据库

<?php

class mysql{
    private $db_name;
    private $db_host;
    private $db_user;
    private $db_pwd;
    private $conn;
    private $querysql;
    private $result;
    private $resultarray=array();
    private $row;
    //创建构造函数 数据库名 主机名 用户名 密码
    function __construct($dbname,$dbhost,$dbuser,$dbpwd){
        $this->db_name=$dbname;
        $this->db_host=$dbhost;
        $this->db_pwd=$dbpwd;
        $this->db_user=$dbuser;
    }
    //连接数据库
    private function db_connect(){
        $this->conn = mysqli_connect($this->db_host,$this->db_user,$this->db_pwd,$this->db_name) or die("Could not Connect MySql Server");
        return $this->conn;
    }

    //选择数据库
    private function selectdb(){
        mysql_select_db($this->db_name) or die("unable to select dbname");
    }

    //执行sql语句
    private function query($sql){
        $conn = self::db_connect();
        return $this->result=mysqli_query($conn,$sql);
    }

    //$result返回值为 bool类型 false为没有数据
    private function get_num($result){
        return $this->num=mysqli_num_rows($result);
    }

    //执行结果 返回数据
    public function get_result($sql){
        $result = $this->query($sql);
        if($this->get_num($result)>0){
            //mysql_fetch_assoc()和 mysql_fetch_array(,MYSQL_ASSOC)从结果集中取得一行作为关联数组 没有则返回false
            while($this->rows=mysqli_fetch_array($result)){
            //赋值 数组赋值 resultarray[]= 将影响的行数赋值给数组
            $this->resultarray[]=$this->rows;
            }
            return $this->resultarray;
        }else{
            echo "暂无数据!";
        }
    }

    //版本信息
    function version() {
         $conn = self::db_connect();
        return mysqli_get_server_info($conn);
    }

    //关闭资源
    function close() {
        $conn = self::db_connect();
        return mysqli_close();
    }

    //向$table表中插入值
    function fn_insert($table,$name,$value){
        $this->query("insert into $table ($name) value ($value)");
    }

    //根据$id值删除表$table中的一条记录
    function fn_delete($table,$id,$value){
        $this->query("delete from $table where $id=$value");
        echo "id为". $id." 的记录被成功删除!";
    }

}


$m = new mysql("admin","127.0.0.1","root","root");
$arreresult = $m->get_result("select * from yii_msg");