The system I'm currently working on has a policy in which objects that have no relationships can be freely deleted, while those that do must be logically deleted. This is meant to prevent historical information from being deleted.

我目前正在处理的系统有一个策略,其中没有关系的对象可以自由删除,而那些必须在逻辑上删除的对象。这是为了防止删除历史信息。

So basically, what I was trying to do was determine whether an object's key is currently present in another table. If it isn't I would simply call delete(), otherwise I would set a property that indicates a logical delete, and call update().

所以基本上,我试图做的是确定对象的密钥当前是否存在于另一个表中。如果不是,我只会调用delete(),否则我会设置一个指示逻辑删除的属性,并调用update()。

I'm using Spring transaction management, so I'm trying to mess with the session itself as least as possible. My initial approach seemed to work at first, but you'll see that it has a major flaw:

我正在使用Spring事务管理,所以我试图尽可能地混淆会话本身。我最初的方法似乎最初起作用,但你会发现它有一个重大缺陷:

@Transactional
public void deleteObject(SomeEntity object)
{       
    //try to delete
    this.someEntityDAO.delete(object);

    try //force foreign key constraint check
    {
        this.someEntityDAO.flush();
    }
    catch (ConstraintViolationException e)
    {
        //reload object
        object= this.someEntityDAO.loadById(object.getId());

        //save as inactive instead of deleting
        object.setActive(false);
        this.someEntityDAO.update(object);
    }
}

Since Hibernate exceptions are fatal, this is completely unreliable (even though it works). I was wondering if there is a way to do a sort of "peek" operation in which I could test if the delete will fail due to a constraint, without actually performing the operation (and thus invalidating the session). The only thing I can think of is to manually check each related table to see if the id is present, but this would be very tedious and error-prone in tables with many relationships. I want to leverage the constraints that are already in place in the database, if possible.

由于Hibernate异常是致命的,这是完全不可靠的(尽管它有效)。我想知道是否有办法进行某种“偷看”操作,我可以测试删除是否会因约束而失败,而不实际执行操作(从而使会话无效)。我唯一能想到的是手动检查每个相关的表以查看id是否存在,但是在具有许多关系的表中这将是非常繁琐且容易出错的。如果可能的话,我想利用数据库中已有的约束。

1 个解决方案