Java ElementCollection 的 JPQL 选择查询
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JPQL select query for ElementCollection
提问by Zaw Than oo
I have the following entity with enumcollection. I would like to search the user with an enumparameter.
The user might have multiple permission. When I search the users with the parameter like Permission.APPROVE, there may be one or more user who have that permission.
How can I write JPQLquery?
我有以下enum收藏实体。我想用enum参数搜索用户。
用户可能有多个权限。当我使用类似参数搜索用户时Permission.APPROVE，可能有一个或多个用户拥有该权限。我该如何编写JPQL查询？
User.java
用户.java
@Entity
....
public class User implements Serializable {
@ElementCollection(targetClass = Permission.class)
@Enumerated(EnumType.STRING)
@CollectionTable(name = "USER_PERMISSION", joinColumns = @JoinColumn(name = "PERMISSION", referencedColumnName = "ID"))
private List<Permission> permisssionList;
}
Permission.java
权限.java
public enum Permission {
REGISTER, APPROVE, REJECT, CONFIRM;
}
How to write ?
怎么写 ？
public List<User> findUserList(Permission permission) {
Query q = em.createQuery(.....);
result = q.getResultList();
}
采纳答案by Koitoer
From spec
从规格
Enum literals support the use of Java enum literal syntax. The fully qualified enum class name must be specified.
枚举文字支持使用 Java 枚举文字语法。必须指定完全限定的枚举类名。
select u from User u where u.Permission = XX.XX.Permission.APPROVE
Try this one.
试试这个。
String jpql =
"select u from User u join u.permission p"
+ " where p = :enumeration";
Query query = em.createQuery(jpql);
query.setParameter("enumeration", XX.XX.Permission.APPROVE);
回答by Camilo
@Embeddableand @CollectionTableare just a simple way to map One To Many relationships, they can not be queried directly nor persisted, but certainly can be joined, do it like you would with any One To Many relationship:
@Embeddable并且@CollectionTable只是映射一对多关系的一种简单方法，它们不能直接查询也不能持久化，但当然可以加入，就像处理任何一对多关系一样：
"select user from User user join user.permissionList p where p = :permission"
and pass the enum as a regular parameter
并将枚举作为常规参数传递
