Grails：如何查询域类？ hasMany-relationship 反对相交的对象集？
我有以下内容：
class Object_1 {
static hasMany = [tags:Tag]
Set tags;
...
}
现在我有一组标签，并且想要查找具有相交（！=匹配）标签的所有 Object_1 实例。我正在考虑类似的事情
Object_1.findAllByTagsInList(tags);
，但这根本不起作用 - 我得到一个“嵌套异常是 org.hibernate.exception.SQLGrammarException：无法执行查询”。我有一种感觉，我错过了一些重要的事情。非常感谢帮助。
I have about the following:
class Object_1 {
static hasMany = [tags:Tag]
Set tags;
...
}
Now I have a set of tags and want to find all Object_1-instances with intersecting (!= matching) tags. I was thinking of something like
Object_1.findAllByTagsInList(tags);
But that does not work at all - I get a "nested exception is org.hibernate.exception.SQLGrammarException: could not execute query". I have the feeling I am missing something important. Help highly appreciated.
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我实际上找到了解决问题的优雅方法。我将关系重新设计为多对多，这样可以简单地迭代标签列表来查找所有相关对象。
...当然现在我必须多次处理这种关系 - 但我很高兴能在很少的地方进行这种工作。
I actually found an elegant way to solve the problem. I redesigned the relationship to be many-to-many which allows for simply iterating over the tags list finding all the relevant objects.
... of course now I have to take care of that relationship a couple of times - but I am happy to have this working with few locs.
“in list”不是动态查找方法中识别的运算符之一 - 这是行不通的。
相反，您必须使用 HQL 或条件生成器 来制定您的查询（也许将其放入静态查找方法中）。
"in list" is not one of the operators recognized in dynamic finder methods - that won't work.
Instead, you'll have to use HQL or the criteria builder to formulate your query (and perhaps put it in a static finder method).