将日期时间字段作为主键会引发致命错误 [英] Taking a datetime field into primary key throws fatal error

问题描述

我想使用两个外键和日期时间字段的组合作为我的组合主键.

I would like to use the combination of two foreign keys plus the datetime field as my combined primary key.

但是我得到了一个

可捕获的致命错误:无法转换类 DateTime 的对象串入C:developmentxampphtdocshappyfacesvendordoctrineormlibDoctrineORMUnitOfWork.php第1337行

Catchable Fatal Error: Object of class DateTime could not be converted to string in C:developmentxampphtdocshappyfacesvendordoctrineormlibDoctrineORMUnitOfWork.php line 1337

当我这样做时.一旦我从我的 YML 实体声明中删除 id: true ，一切都会恢复正常.

when I do so. As soon as I remove the id: true from my YML entity declaration everything works fine again.

这里出现了什么问题?对我来说，这似乎是一个 Symfony2 或 Doctrine2 错误，因为如果我不将 datetime 列声明为主键的一部分，则数据库中的日期时间设置得很好.

What is the problem that occurs here? It seems to be rather a Symfony2 or a Doctrine2 bug to me, because the datetime is set fine in the database if I don't declare the datetime column to be part of the primary key.

有人可以提供帮助或建议吗?

Can anyone help or advise?

推荐答案

这是不可能的，也不推荐.对于主键，重点关注原始数据类型，例如 Integer 或 String.大多数 RDMS 系统更喜欢 Integer 作为主键以获得最大性能.

Its not possible and not recommended. For primary key focus on primitive data types such as Integer or String. The most RDMS System prefer Integer as primary key for maximum performance.

看看:http://doctrine-orm.readthedocs.org/en/2.1/tutorials/composite-primary-keys.html

也许可以通过添加新的 Doctrine 数据类型来解决问题.使用 __toString() 函数，但我认为 Doctrine 会强制您只使用原始数据类型.

Maybe a workaround could work by adding a new Doctrine data type. With a __toString() function, but I think Doctrine will force you to use primitive data types only.

class Foo
{
    private $bar = 'test';

    public function __toString()
    {
        return $this->bar;
    }
}

echo new Foo();

您的错误通常意味着 DateTime 没有 __toString() 函数或与字符串不兼容.我从未测试过它使用自定义数据类型作为主键.所以你必须自己尝试一下.

Your error means in general DateTime has no __toString() function or is not string compatible. I never tested it to use a custom data type as primary key. So you've to try it yourself.

看一看:http://docs.doctrine-project.org/projects/doctrine-dbal/en/latest/reference/types.html

另一个尝试是使用 String 作为主键并使用

Another try is use String as Primary key and set your id with

$entity->setId(new DateTime()->format('yyyy/mm/dd'));

这是一个类似的问题:Symfony/Doctrine: DateTime as primary key

这篇关于将日期时间字段作为主键会引发致命错误的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！