我正在将KodoJDO的应用程序移植到Hibernate。我有一个查询,该查询跨越数据库中的4个表和Java代码中的3个对象。
用英语查询是查找在系统X中具有权利的用户。
我在用户对象上调用的JDOQL where子句是其中entitlements.contains(ent)&&(upper(ent.system.id)='EVPN')
执行查询的一些SQL是:
select unique(u.id)
from USER u, USERENTITLEMENT ue, ENTITLEMENT e, SYSTEM s
where u.id = ue.userid
and ue.entitlementid = e.id
and e.systemid = s.id
and s.id = 'evpn'
我对HQL的最佳猜测给了我一个例外
org.hibernate.hql.ast.QuerySyntaxException: unexpected AST node: ( [select user from com.ebig.entity.User as user, com.ebig.entity.Entitlement as ent, com.ebig.entity.System as sys where entitlements.contains(ent) and ent.system = sys and sys.id = 'evpn']
数据库的结构如下:
User
id
UserEntitlement
userid
entitlementid
Entitlement
id
systemid
System
id
Java代码的结构如下:
class User
{
String id;
Set<Entitlement> entitlements;
}
class Entitlement
{
String id;
System system;
}
class System
{
String id;
}
更新我的最终查询有效
hqlQuery = "select distinct user from User as user "+
"inner join user.entitlements as entitlement inner join entitlement.system as system "+
"where system.id = 'evpn' AND mod(user.flags, 2) = 0 AND source = 1";
是的,我知道我应该使用参数,但是我有很多问题要解决,并且将代码推迟一天。
具有隐式内部联接以获取系统权利的另一种形式
hqlQuery = "select distinct user from User as user "+
"inner join user.entitlements as entitlement "+
"where entitlement.system.id = 'evpn' AND mod(user.flags, 2) = 0 AND source = 1";
select distinct u.id from User u
inner join u.entitlements as entitlement
inner join entitlement.system as system
where system.id = :evpn
其中:evpn是您必须绑定的命名参数。
[在执行HQL时必须考虑对象和对象之间的关系,而不要考虑表,外键和联接表。