Grails GORM 自引用属于删除与预期相反的方向

发布于 2024-10-28 08:39:59 字数 559 浏览 7 评论 0原文

我有一个 Grails 域类，它是类别的层次结构。每个类别都有一个父类别（根类别除外，该类别为空）。

class Category {
    String name

    static mapping = {
        cache true
        name index:'category_name_idx'
    }

    static belongsTo = [parent:Category]

    static constraints = {
        parent(nullable:true)
    }
}

我的问题：删除级联与我的预期完全相反：

someSubCategory.delete() 删除类别，然后尝试删除父类别（如果父类别有其他子类别，则会因完整性违规而失败）。
ParentCategory.delete() 不会级联删除其子级，而是会因完整性冲突而失败。

我做错了什么？我的理解是，上面的“belongsTo”应该告诉 GORM 将删除从父级级联到所有子级，而不是从子级级联到其父级。

原文

I have a Grails domain class that is a hierarchy of categories. Each Category has a parent category (except for the root category which is null).

class Category {
    String name

    static mapping = {
        cache true
        name index:'category_name_idx'
    }

    static belongsTo = [parent:Category]

    static constraints = {
        parent(nullable:true)
    }
}

My problem: deletes cascade exactly opposite of what I'd expect:

someSubCategory.delete() deletes the category then tries to delete the parent category (which fails with an integrity violation if the parent has other children).
parentCategory.delete() does NOT cascade delete its children, but instead just fails with an integrity violation.

What am I doing wrong? My understanding is that the 'belongsTo' above should tell the GORM to cascade deletes from the parent to all children, but not from a child to its parent.

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可是我不能没有你 2024-11-04 08:39:59

如果我理解正确，一个类别属于一个父级，并且一个父级可以有多个子级，所以我认为您需要一个 hasMany 关系，如下所示：

class Category {
    String name

    static mapping = {
        cache true
        name index:'category_name_idx'
    }

    static belongsTo = [parent:Category]
    static hasMany = [children: Category]

    static constraints = {
        parent(nullable:true)
    }
}

我有类似的结构，并且从来没有以这种方式进行删除的问题。

希望这有帮助！

If I am understanding correctly a Category belongs to a parent and a parent can have multiple children, so I think you need a hasMany relationship, something like this:

class Category {
    String name

    static mapping = {
        cache true
        name index:'category_name_idx'
    }

    static belongsTo = [parent:Category]
    static hasMany = [children: Category]

    static constraints = {
        parent(nullable:true)
    }
}

I had had similar structures and never have issues with the delete doing it this way.

Hope this helps!

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挽心 2024-11-04 08:39:59

这不是答案，但我找到了解决我自己问题的方法。您可以删除belongsTo = [parent:Category]，用一个简单的实例变量替换它。这会阻止 subCategory.delete() 级联到父级。

class Category {
    String name
    Category parent

    static mapping = {
        cache true
        name index:'category_name_idx'
    }

    static constraints = {
        parent(nullable:true)
    }
}

It's not an answer, but I found a workaround to my own question. You can remove the belongsTo = [parent:Category], replacing it with a simple instance variable. This stops subCategory.delete() from cascading to the parent.

class Category {
    String name
    Category parent

    static mapping = {
        cache true
        name index:'category_name_idx'
    }

    static constraints = {
        parent(nullable:true)
    }
}

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