Hibernate查询：一个Set是否包含某个Object？ [英] Hibernate query: does a Set contains a certain Object?

问题描述

我有两个Hibernate数据对象。第一个是用户（具有唯一的ID，用户名等），第二个是可协作的类。在这两者之间有一个n-to-m关系（用Sets实现）。这意味着，用户可以在许多Collaborationable上工作，而Collaborationable可以有许多用户。此外，Collaborationable只有一个用户作为所有者。

I have two Hibernate data object. The first is a User (with unique id, username etc.) and the second is the class Collaborateable. Between this two there is a n-to-m relation (implementet with Sets). That means, a User works on many Collaborateables and a Collaborateable has many users. In addition a Collaborateable has exactly one User as owner.

<class name="CollaborateableImpl" table="Collaborateable">
<id name="id" type="int" column="id">
    <generator class="increment" />
</id>

<property name="name" column="name" type="string" not-null="true" />
<property name="keywords" column="keywords" type="string"/>

<!-- Collaborateable has a Registered User as owner -->
<many-to-one name="owner" class="UserImpl" fetch="select">
        <column name="User_id_owner" not-null="true" />
</many-to-one>

<!-- Users that collaborate on this Collaborateable -->
<set name="users" table="CollaborateOn" inverse="false">        
        <key column="Collaborateable_id" />         
        <many-to-many column="User_id" class="UserImpl" />    
</set>

我想实现一个Hibernate查询，用于搜索具有特定用户作为所有者的Collaborationable或包含Collaborationable.users集中的相同特定用户的Collaborationable。另外，还应该有一个简单的WHERE子句来检查关键字。

i would like to implement a Hibernate query, that searches for Collaborateables that have a certain user as owner OR containing the same certain User in the Collaborateable.users Set. In addition, there should also be a simple WHERE clause to check for Keywords.

有没有像Hibernate中的CONTAINS运算符那样的东西？

Is there something like a CONTAINS operator in Hibernate?

例如：

For example:

FROM CollaborateableImpl WHERE (owner = :user OR users CONTAINS :user) AND keywords like '%:searchString%'

否则，你知道如何通过连接来解决这个问题吗？

Otherwise, do you know how to solve this problem with a join?

推荐答案

您正在寻找 elements 关键字。

select c 
FROM CollaborateableImpl c 
WHERE (
    c.owner = :user 
    OR :user in elements(c.users)
)
AND c.keywords like '%:searchString%'

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