Doctrine2在另一个's迭代中创建新查询 - Doctrine2 create new query inside another's iteration breaks loop

Doctrine2 create new query inside another's iteration breaks loop

我试图在游标迭代中获取一些结果，所以我得到相关的元素和东西。但是，当在迭代中执行此查询时，迭代游标死亡，迭代将结束，即使有更多的数据要获取。

一个例子

protected $em;
public function __construct() {
    $this->em = $this->get('doctrine')->getManager('default');
}
public function getProducts() {
    $query = "SELECT * FROM products"; // 100 Products
    $stmt = $this->select($query);
    while($result = $stmt->fetch()) {
        // This breaks the cursor so only 1 product is parsed.
        // If I remove this line, iteration ends perfectly (100 products)
        $pictures = $this->getPictures($result['id']);
    }
}
public function getPictures($product) {
    $query = "SELECT * FROM pictures WHERE product_id = :product_id";
    $stmt = $this->select($query, array('product_id' => $product));
    return $stmt->fetchAll();
}
public function select($query, array $params = array()) {
    $conn = $this->em->getConnection();
    $stmt = $conn->prepare($query);
    foreach($params as $key => $value) {
        $stmt->bindValue($key, $value);
    }
    $stmt->execute();
    return $stmt;
}

我认为如果不关闭前一个光标，就不能使用另一个光标。如果您查看ResullStatement接口:

/**
 * Closes the cursor, enabling the statement to be executed again.
 *
 * @return boolean TRUE on success or FALSE on failure.
 */
public function closeCursor();

当游标关闭时，通常会释放stmt内存。那么，为什么不为此编写一个查询呢?您可以使用子查询提取所有产品id。比如: