java 使用内部联接的简单 hql 命名查询
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Simple hql named query that uses a inner join
提问by NimChimpsky
I want to do something like this in my domain/entity object :
我想在我的域/实体对象中做这样的事情：
@Entity
@NamedQueries({
@NamedQuery(name="favouriteCats", query="from Cat c inner join on UserCat uc where uc.isFavourtie = true and uc.user = :user")
})
public final class Cat extends BaseTable
So that in my service layer I can do this :
所以在我的服务层我可以这样做：
Query query = session.getNamedQuery("favouriteCats")
query.setParameter(0, MyUser);
return query.list();
However, my syntax in HQL is incorrect - and aftern ten minutes looking at official docs I have decided to give up and ask here ... ? My usercat table is joined like so :
但是，我在 HQL 中的语法不正确 - 看了十分钟的官方文档后，我决定放弃并在这里问......？我的 usercat 表是这样加入的：
@ManyToOne(cascade = CascadeType.MERGE)
@JoinColumn(name="cat_fk", insertable=false, updatable=false)
private cat
The sql is this, it works fine at my db command prompt:
sql 是这样的，它在我的 db 命令提示符下工作正常：
select c.*
from cat as c inner join usercat as uc on c.id = uc.cat_fk
and uc.isFavourite = 1 //bit field
and uc.user_fk = 74 //just user id
Is it just me or is the hibernate documentation rather painful, and do you find yourself often wondering whether it would be quicker just to write normal jdbc prepared statements to populate your pojos/domain objects/dto's... ?
是我还是 hibernate 文档相当痛苦，您是否发现自己经常想知道仅编写普通的 jdbc 准备好的语句来填充您的 pojos/域对象/dto 是否会更快...？
回答by col
I think this might work for you, but I am guessing your Usercat class here:
我认为这可能对你有用，但我猜你的 Usercat 类在这里：
select c from Usercat as uc inner join uc.cat as c where uc.isFavourtie = true and uc.user = :user
回答by coding_idiot
Case Issue, Right query would be:
案例问题，正确的查询将是：
from Cat c inner join on Usercat uc where uc.isfavourtie = true and uc.user = :user
Note : C in Cat is capital, U in Usercat is capital where as c in Usercat is small and f in isfavourite is small.
注意：Cat 中的 C 是大写的，Usercat 中的 U 是大写的，因为 Usercat 中的 c 较小，而 isfavourite 中的 f 较小。
