使用具有参数的GORM在一对一Grails域上加入查询 [英] join query on one-to-one Grails domain using GORM with parameters

问题描述

我有两个Grails domain类，可以这样说:

I have a two Grails domain class, let say:

class Hero {
    String name
    Float level

    Familiar familiar
}

class Familiar {
    String name
    Integer raceId
}

现在，我要检索的所有Hero具有Familiar的名称都类似于给定String的名称，例如 example :"hachiko".要使用SQL进行此操作，我需要执行的查询与此类似:

Now, what I want is to retrieve all Hero having Familiar with the name similar to a given String, for example: "hachiko". To do that using SQL, all I need is to perform a query similar to this:

SELECT h.name, h.level
FROM HERO h JOIN FAMILIAR f ON h.id = f.ownerId
WHERE f.name LIKE '%hachiko%'

但是如何在Grails上执行此操作?这是我的代码:

But how can I do that on Grails? This is my code:

String filter = "hachiko"
def hero = Hero.executeQuery(
    "SELECT h.name, h.level FROM HERO h JOIN h.familiar WHERE h.id = " +
    "h.familiar.ownerId and h.familiar.name LIKE :filter",
    [filter, "%$filter%"]
)

这项工作吗?我应该创建那些static属性(hasOne，belongsTo)，并将它们放在哪里?因为到目前为止，没有这些static属性，我收到的是error消息:

Would this work? Should I create those static properties (hasOne, belongsTo), and where should I place them? Because so far, without those static properties, I'm receiving an error message:

ORA-00904: "HERO0_"."FAMILIAR_ID": invalid identifier

并添加了这些static属性，我得到了:

And having those static properties added, I got this:

org.hibernate.MappingException: hasOne property [Hero.familiar] is not bidirectional. Specify the other side of the relationship!

他们的关系是一对一的可选. (例如，一个Hero最多可以包含一个Familiar)，并且Familiar的id与Hero相同.

Their relationship is optional one-to-one. (e.g. A Hero can have at most one Familiar), and the id of the Familiar is the same of it's Hero.

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