Hi,

I am new bie at hibernate. I need someone's help.
What I need hibernate to use left outer join in it's query as default.
Suppose, I have two table 1) Employee 2) Task with one to many relationship.
Now If I say findbyquery("select count(*) from Task t order by t.Employee.Name")
Hibernate generate following query with inner join:
select count(*) as col_0_0_ from Task Task0_, Employee Employee1_ where Task0_.Employee_ID=Employee1_.Employee_ID order by Employee1_.NAME
Now, I want hibernate to generate following query with left outer join to get all data with from Task despite null in EmployeeId.
select count(*) as col_0_0_ from Task Task0_
left outer join Employee Employee1_
on Task0_.Employee_ID=Employee1_.Employee_ID
order by Employee1_.NAME

I set fetch=join in hbm files of both Employee and Task but still it uses inner join only.
I am using hibernate3.0.

Please somebody suggest.

Thanks in Advance.

Hi,

Here is an important thing to know about join fetching:

fetch="join" uses outer join for nullable many-to-one foreign keys and collections
fetch="join" uses inner for not-null many-to-one foreign keys

Hi,

Thanks for response.

I did not define "not-null = true" at both relation that means those are nullable as default.

And still it returns result according to inner join way.

It does not return as same result as I get result by running same query at db side with outer join.

Please suggest how to tell hibernate to write outer join insted of inner join when I use any field from association in query.

Thanks

Hi,

The first time I didn't realize you were using HQL Queries to retrieve data ...
HQL queries do not respect any fetch="join" defined in the mapping document!
The fetch="join" is only used when retrieving data through get() or load().
If you want an HQL Query to use left outer join, you have to write it explicitly in your query!

Ohh is it?

Then my task would become really tougher as my hibernate query is generated on fly as per the meta data we store
at database level. Our user store columns name in database to be displayed at UI for each table so if they define any column which is part of association type of column, suppose for Tast table user define Id, Name, Employee.Name then
my code generate HQL on fly to fetch only these columns but i get only inner join data.

I might have to change my implementaion if HQL does not care about fetch="join".

Thanks a lot for making me clear about this.

You can take a look at this article:

http://community.jboss.org/wiki/AShortP ... Strategies

It was very instructive for me when I first read it!

Yes it is really instructive me too.

I think this might be the limitation that HQL does not respect fetch="join" and so I might have to change my implementation by using criteria query.

Thanks for all your help and quick responses.