Question

当我使用FETCH_CLASS时会出现以下错误，但是当我使用FETCH_OBJ时，页面会正确加载。请帮我解决这个问题。

错误是：

致命错误：未捕获PDOException：SQLSTATE [HY000]：常规错误：获取模式需要C：\ xampp \ htdocs \ Work \ AppDarbNajah \ App \ Database.php中的classname参数：51堆栈跟踪：＃0 C：\ xampp \ htdocs \ Work \ AppDarbNajah \ App \ Database.php（51）：PDOStatement-＆gt; setFetchMode（8）＃1 C：\ xampp \ htdocs \ Work \ AppDarbNajah \ App \ Model \ Model.php（62）：App \ Database-＆gt;查询（＆＃39; SELECT \ r \ n ...＆＃39;，false，＆＃39; App \ Entity \ Arti ...＆＃39;）＃2 C：\ xampp \ htdocs \ Work \ AppDarbNajah \ App \ Model \ ArticleModel.php（9）：App \ Model \ Model-＆gt; query（＆＃39; SELECT \ r \ n ...＆＃39;）＃3 C：\ xampp \ htdocs \ Work \ AppDarbNajah \ App \ Controller \ ArticleController.php（16）：App \ Model \ ArticleModel-＆gt; load（）＃4 C：\ xampp \ htdocs \ Work \ AppDarbNajah \ Public \ index.php（33）：App \ Controller \ ArticleController-＆gt; index（）＃5 {main}在第51行的C：\ xampp \ htdocs \ Work \ AppDarbNajah \ App \ Database.php中抛出

数据库的代码：

<?php
namespace App;
use \PDO;
/* Connect to a MySQL database using driver invocation */
class Database{
    private $db_host;
    private $db_name;
    private $db_user;
    private $db_pass;
    private $pdo;

    public function __construct($db_name,
                                $db_host = 'localhost',
                                $db_user = 'root',
                                $db_pass = ''){
        $this->db_name = $db_name;
        $this->db_host = $db_host;
        $this->db_user = $db_user;
        $this->db_pass = $db_pass;
    }

    private function getPDO() {
        if($this->pdo === null){
            $pdo = new PDO(
                    'mysql:host='.$this->db_host.';dbname='.$this->db_name,
                    $this->db_user,
                    $this->db_pass
                );
            $pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
            $pdo->query('
                        SET NAMES utf8;
                        SET CHARACTER SET UTF8
                    ');
            $this->pdo = $pdo;
        }
        return $this->pdo;
    }
    public function query($statement, $one = false, $class = null){  
        $rs = $this->getPDO()->query($statement);
        if(
           strpos(strtolower($statement), 'insert') === 0 ||
           strpos(strtolower($statement), 'delete') === 0 ||
           strpos(strtolower($statement), 'update') === 0 

        ){
            return $rs;
        }
        if($class === null){
            $rs->setFetchMode(PDO::FETCH_OBJ);
        } else {
            $rs->setFetchMode(PDO::FETCH_CLASS);
        }
        if($one){
            $data = $rs->fetch();
        } else {
            $data = $rs->fetchAll();
        }

        return $data;
    }
    public function prepare($statement, $attributes, $one = false, $class = null){
        $rs = $this->getPDO()->prepare($statement);
        $rst = $rs->execute($attributes);

        if(
           strpos(strtolower($statement), 'insert') === 0 ||
           strpos(strtolower($statement), 'delete') === 0 ||
           strpos(strtolower($statement), 'update') === 0 

        ){
            return $rst;
        }
        if($class === null){
            $rs->setFetchMode(PDO::FETCH_OBJ);
        } else {
            $rs->setFetchMode(PDO::FETCH_CLASS);
        }
        if($one){
            $data = $rs->fetch();
        } else {
            $data = $rs->fetchAll();
        }

        return $data;
    }
}

模型的2代码：

<?php
namespace App\Model;
use App\Database;

class Model{
  protected $db;
  protected $table;

  public function __construct(Database $db){
     $this->db = $db;
     //var_dump(get_class($this));
  }
  public function create($fields){
     var_dump($fields);
     $sql_pairs = [];
     $attributes = [];
     foreach ($fields as $k =>$v){
        $sql_pairs[] = "$k = ?";/*راجع درس PDO*/
        $attributes[] = $v;
     }
     $sql_parts = implode(', ', $sql_pairs);         

     $this->query("INSERT INTO {$this->table} SET $sql_parts", $attributes);
  }
  public function update($id, $fields){

  }
  public function delete($id){

  }
  public function search($id, $fields = null){

  }
  public function query($statement, $attributes= null, $one = false){
     var_dump(get_class($this));
     var_dump(str_replace('Model', 'Entity', get_class($this)));
     //die();
     if($attributes){
        return $this->db->prepare(
           $statement,
           $attributes,
           $one,
           str_replace('Model', 'Entity', get_class($this))
        );
     } else{
        return $this->db->query(
           $statement,
           $one,
           str_replace('Model', 'Entity', get_class($this))
        );
     }
  }      
}

Answer 1

这正是错误所说的：

获取模式需要classname参数

你有：

$rs->setFetchMode(PDO::FETCH_CLASS);

如manual所述，可能的情况是：

public bool PDOStatement::setFetchMode ( int $mode )
public bool PDOStatement::setFetchMode ( int $PDO::FETCH_COLUMN , int $colno )
public bool PDOStatement::setFetchMode ( int $PDO::FETCH_CLASS , string $classname , array $ctorargs )
public bool PDOStatement::setFetchMode ( int $PDO::FETCH_INTO , object $object )

如果你想传递PDO::FETCH_CLASS作为第一个参数，你绝对需要传递另外两个参数。否则，PDO如何知道它需要创建哪个类实例？

致命错误：未捕获PDOException：SQLSTATE [HY000]：常规错误：获取模式需要classname参数in

1 个答案: