PDO的使用

• 本文可以结合我的文章设计模式中的-单例模式
  再进行封装下
  使用类时使用以下代码即可

$pdo = DBPDO::get_instance();
$pdo->test();

$user='root';
    $pass='123456';
    $dsn='mysql:host=localhost;dbname=test';
    //$pdo = new PDO($dsn,$user,$pass);
    //
    try{
        //创建pdo对象
        $pdo=new PDO($dsn,$user,$pass);
        $pdo->setAttribute(PDO::ATTR_ERRMODE,2);//异常报错
        $pdo->exec("set names utf8");
    }catch(PDOException $e){
        echo $e->getMessage();
    }
    //$sql="insert into dlxxx(payamount,username,remark,orderid,payip,paytype,returnurl,notifyurl,version,consdition)values(?,?,?,?,?,?,?,?,?,?)";
    $sql = "insert into users(username,password,amount) values(?,?,?)";
    $stmt = $pdo->prepare($sql);
    $aa = '2';
    $stmt->bindParam(1,$user);//不能直接给数据
    $stmt->bindParam(2,$pass);
    $stmt->bindParam(3,$aa);
    $ss = $stmt->execute();
    var_dump($ss);

注意bindParam()绑定的参数必须是一个变量 ,bindValue()既可以绑定变量，又可以绑定具体值

PDO连接数据库的类

<?php

//定义数据库信息

header("Content-type:text/html; charset=utf-8");

define('DB_HOST', 'localhost');
define('DB_USER', 'root');
define('DB_PWD', '123456');
define('DB_NAME', 'test');

class DBPDO {

    private static $instance;
    public $dsn;
    public $dbuser;
    public $dbpwd;
    public $sth;
    public $dbh;

    //初始化
    function __construct() {
        $this->dsn = 'mysql:host='.DB_HOST.';dbname='.DB_NAME;
        $this->dbuser = DB_USER;
        $this->dbpwd = DB_PWD;
        $this->connect();
        $this->dbh->query("SET NAMES 'UTF8'");
        $this->dbh->query("SET TIME_ZONE = '+8:00'");
    }

    //连接数据库
    public function connect() {
        try {
            $this->dbh = new PDO($this->dsn, $this->dbuser, $this->dbpwd);
        }
        catch(PDOException $e) {
            exit('连接失败:'.$e->getMessage());
        }
    }

    //获取表字段
    public function getFields($table='vista_order') {
        $this->sth = $this->dbh->query("DESCRIBE $table");
        $this->getPDOError();
        $this->sth->setFetchMode(PDO::FETCH_ASSOC);
        $result = $this->sth->fetchAll();
        $this->sth = null;
        return $result;
    }

    //插入数据
    public function insert($sql) {
        if($this->dbh->exec($sql)) {
            $this->getPDOError();
            return $this->dbh->lastInsertId();
        }
        return false;
    }

    //删除数据
    public function delete($sql) {
        if(($rows = $this->dbh->exec($sql)) > 0) {
            $this->getPDOError();
            return $rows;
        }
        else {
            return false;
        }
    }

    //更改数据
    public function update($sql) {
        if(($rows = $this->dbh->exec($sql)) > 0) {
            $this->getPDOError();
            return $rows;
        }
        return false;
    }

    //获取数据
    public function select($sql) {
        $this->sth = $this->dbh->query($sql);
        $this->getPDOError();
        $this->sth->setFetchMode(PDO::FETCH_ASSOC);
        $result = $this->sth->fetchAll();
        $this->sth = null;
        return $result;
    }

    //获取数目
    public function count($sql) {
        $count = $this->dbh->query($sql);
        $this->getPDOError();
        return $count->fetchColumn();
    }

    //获取PDO错误信息
    private function getPDOError() {
        if($this->dbh->errorCode() != '00000') {
            $error = $this->dbh->errorInfo();
            exit($error[2]);
        }
    }

    //关闭连接
    public function __destruct() {
        $this->dbh = null;
    }
}

//eg: an example for operate select

$test = new DBPDO;

$sql = "SELECT * FROM `users`";

$rs = $test->select($sql);

print_r($rs);
    注意，插入语句的准备，不可以直接$pdo->prepare($sql),因为此时的$pdo已经是对象实例化之后的PDO类，而类里面没有prepare()这个函数
    $pdo->dbh才相当于我们使用的$pdo
    $stmt = $pdo->dbh->prepare($sql);





?>