我开始通过在youtube(phpacademy)上观看教程来构建oop登录/注册系统,我得到了一点,代码不起作用。我检查了几次,但仍然没有。数据库创建并运行良好,我在db(用户)-alex中有一个用户。 如果有人能看到我做错了什么,请帮助我:)。
我希望我能正确解释我的问题,我得到的错误是:“致命错误:在第7行的C:\ xampp \ htdocs \ oopLogin \ index.php中的非对象上调用成员函数count() “
db.php中
<?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->_results = $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;
}
}
index.php
<?php
require_once 'core/init.php';
$user = DB::getInstance()->get('users', array('username', '=', 'alex'));
if(!$user->count()) {
echo 'No user';
} else {
foreach($user->results() as $user) {
echo $user->username, '<br>';
}
}
答案 0 :(得分:3)
你的SQL查询错了!
在DB类中更改此行
来自:
$sql = "($action) FROM ($table) WHERE ($field) ($operator) ?";
到
$sql = "{$action} FROM {$table} WHERE {$field} {$operator} ?";