Hibernate HQL: how to use a complex left join fetch
I want to add a left join on TASK table when the following condition occurs: LEFT JOIN FETCH PROMPT p on (t.id = p.task.id and p.applicationName in ('XXX'))
Here is my hql query:
select
distinct t
from
TASK t
LEFT JOIN FETCH
SERVER ser
on t.id=ser.task_id
LEFT JOIN FETCH
APPLICATION app
on ser.id=app.server_id
LEFT JOIN FETCH
PROMPT p on (t.id = p.task.id and p.applicationName in ('XXX'))
where
t.id=ser.task.id
and ser.id=app.server
and app.name in ('XXX')
order by t.id
I get the following exception, probably due to "on" keyword:
java.lang.NoSuchMethodError: org.hibernate.hql.antlr.HqlBaseParser.recover(Lantlr/RecognitionException;Lantlr/collections/impl/BitSet;)V
at org.hibernate.hql.antlr.HqlBaseParser.queryRule(HqlBaseParser.java:771)
Any ideas?
class Task {
private String taskId;
private Set<ServerDetails> servers;
}
class ServerDetails {
private String id;开发者_运维技巧
private Set<ApplicationDetails> applications;
}
class ApplicationDetails {
private String id;
}
Class Prompt {
private String applicationName;
}
How can i use left join fetch using my condition p.applicationName in ('XXX')?
There are several problems here:
- Your HQL as you've posted it is not really HQL :-) It's straight up SQL. For HQL you need use mapped associations to join tables. See below for an improved version.
- As far as I'm aware
ON
clause does not support multiple joined conditions in parenthesis. NoSuchMethodError
is not something Hibernate would throw :-) You likely have an older version ofantlr.jar
somewhere in your classpath and it gets picked up in place of the one expected by Hibernate. Find it and remove it.
Without seeing your mappings the following is likely inaccurate, but I'll take a stab at writing the more appropriate HQL:
select distinct t
from TASK t
left join fetch t.server ser
left join fetch ser.application app
left join t.prompt p with p.applicationName in ('XXX')
order by t.id
Note that prompt
is not fetched because you can't use join fetch
together with with
condition. You can replace it with inner join fetch
and where
if the association is required.
If you're still having trouble after the classpath issue is resolved, feel free to post your mappings if you need help with actual HQL.
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