php - 为foreach()提供的参数无效

时间:2013-12-07 17:44:49

标签: php mysql class pdo

嘿,我尝试使用foreach函数,我得到了这个错误...我的代码是这样的。

我的index.php

require_once 'core/init.php';
$user = DB::getInstance()->get('users', array('username', '=', 'kostas'));
if(!$user->count()) {
    echo "No user";
}else {
    foreach ($user->results() as $user) {
        # code...
        echo $user->username, '<br>';
    }
}

我的DB.php有这些功能

<?php
class DB {
    private static $_instance = null;
    private $_pdo, 
            $_query, 
            $_error=false, 
            $_results, 
            $_count=0;
    private function __construct(){
        try{
            $this->_pdo = new PDO('mysql:host=' . Config::get('mysql/host') . ';dbname=' . Config::get('mysql/db'), Config::get('mysql/username'), Config::get('mysql/password'));
        }catch(PDOException $e){
            die($e->getMessage());
        }
    }
    public static function getInstance(){
        if(!isset(self::$_instance)){
            self::$_instance = new DB();
        }
        return self::$_instance;
    }
    public function query($sql, $params = array()) {
        $this->_error = false;
        if($this->_query = $this->_pdo->prepare($sql)){
            $x = 1;
            if(count($params)){
                foreach ($params as $param) {
                    $this->_query->bindValue($x, $param);
                    $x++;
                }
            }
            if($this->_query->execute()){
                $this->_reults = $this->_query->fetchAll(PDO::FETCH_OBJ);
                $this->_count = $this->_query->rowCount();
            }else{
                $this->_error = true;
            }
        }
        return $this;
    }
    public function action($action, $table, $where = array()) {
        if(count($where) === 3) {
            $operators = array('=', '>', '<', '>=', '<=');
            $field      = $where[0];
            $operator   = $where[1];
            $value      = $where[2];
            if(in_array($operator, $operators)){
                $sql = "{$action} FROM {$table} WHERE {$field} {$operator} ?";
                if(!$this->query($sql, array($value))->error()){
                    return $this;
                }
            }
        }
        return false;
    }
    public function get($table, $where) {
        return $this->action('SELECT *', $table, $where);
    }
    public function delete($table, $where) {
        return $this->action('DELETE *', $table, $where);
    }
    public function results() {
        return $this->_results;
    }
    public function error() {
        return $this->_error; 
    }
    public function count() {
        return $this->_count;
    }
}
?>
你可以告诉我这里可能出了什么问题吗? 我的数据库已经在users表中有一个用户名为kostas的表,因此它应该返回结果corectly。

2 个答案:

答案 0 :(得分:1)

为变量尝试不同的名称

 foreach ($user->results() as $u) {
    //# code...
    echo $u->username, '<br>';
}

答案 1 :(得分:1)

foreach ($user->results() as $user) {

你在这里使用相同的变量两次,这可能是问题吗?

您可以重命名其中一个变量。在这里,我将第一个$user重命名为$userQuery,因为我认为这更清楚:

$userQuery = DB::getInstance()->get('users', array('username', '=', 'kostas'));
if(!$userQuery->count()) {
    echo "No user";
}else {
    foreach ($userQuery->results() as $user) {
        # code...
        echo $user->username, '<br>';
    }
}

或者您可以在foreach中重命名变量:

foreach ($user->results() as $usr) {