调用成员函数count（）

Question

我得到一个＆＃34;调用成员函数count（）＆＃34;错误。我已经尝试了各种方法来解决这个问题，但现在我被卡住了。

问题在于：

var_dump($data, $field);

if($user->count()) {
   $this->_data = $data->first();

这是我的代码：

class user {
    private $_db,
    $_data;

    public function __construct($user = null) {
        $this->_db = DB::getInstance(); 
    }

    public function create($fields = array()) {
        if(!$this->_db->insert('users', $fields)) {
            throw new exception('There was a problem creating an account.');
        }
    }

    public function find($user = null) {
        if($user) {
            $field = (is_numeric($user)) ? 'id' : 'username';   
            $data = $this->_db->get('users', array($field, ' = ', $user));

            var_dump($data, $field);
            if($user->count()) {
                $this->_data = $data->first();
                return true;    
            }
        }
        return false;
    }

    public function login($username = null, $password = null) {
        $user = $this->find($username);

        if($user) {
            if($this->data()->password === hash::make($password, $this->data()->$salt)) {

                echo 'OK!';

            }
        }

        return false;
    }

    private function data() {
        return $this->_data;
    }
}

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').'');
            echo 'Connected';

                }   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;
            }

            private 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 insert($table, $fields = array()) {

                        $keys = array_keys($fields);
                        $values = '';
                        $x = 1;

                        foreach($fields as $field) {
                                $values .= '?';
                                if($x < count($fields)) {
                                    $values .= ', ';    
                                }
                            $x++;
                        }


                        $sql = "INSERT INTO users (`". implode('`, `', $keys) . "`) VALUES ({$values})";

                        if(!$this->query($sql, $fields)->error()) {
                                return true;
                        }

                return false;
            }

            public function update($table, $id, $fields) {
                $set = '';  
                $x = 1;

                foreach($fields as $name => $value) {
                    $set .= "{$name} = ?";
                    if($x < count($fields)) {
                        $set .= ', ';
                    }
                    $x++;
                }


                $sql = "UPDATE {$table} SET {$set} WHERE id ={$id}";

                if(!$this->query($sql, $fields)->error()) {
                    return true;    
                }
                return false;
            }

            public function results() {
                return $this->_results; 
            }

            public function first() {
                return $this->_results[0];
            }

            public function error() {
                return $this->_error;
            }

            public function count() {
                return $this->_count;   
            }
}

请帮忙！

Answer 1

修改 您在调用$ this-＆gt; _db-＆gt; get时使用了错误的运算符。你传入＆＃39; =＆＃39;但可接受的运营商是＆＃39; =＆＃39; （空间不足）。结合以下建议可以解决您的问题。

看起来您需要$data->count()而不是$user->count()

public function find($user = null) {
    if($user) {
        $field = (is_numeric($user)) ? 'id' : 'username';   
        $data = $this->_db->get('users', array($field, '=', $user));

        if($data && $data->count() > 0) {
            $this->_data = $data->first();
            return true;    
        }
    }
    return false;
}

你应该使用更好的变量名，你可以在实际值不是用户对象的几个地方使用$ user。

public function find($user = null) {

这是一个数字或字符串，而不是尝试

public function find($queryParam = null) {

$user = $this->find($username);

这是一个布尔值，而不是尝试

$userFound = $this->find($username)'

Answer 2

您的query方法会使用上次执行的查询计数更新属性$_count。您有一个公共方法来访问此属性; count()。您的数据库类对象保存在属性_db中。因此，我们可以做到以下几点;

if($this->_db->count()) {
   $this->_data = $data->first();

Answer 3

如果这段代码：

        $field = (is_numeric($user)) ? 'id' : 'username';   

表示$user有时可能是某个对象以外的东西，为什么你无条件地做

        if($user->count()) {

哪会要求$user始终是一个对象？