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Consider the following association

A <----> B <----->*C

A has a one to one relation with B
B has a one to many relation with C

I have the following query

select a, b, c from A as a inner join a.b as B left outer join b.c as C where a.attrib in ('zzz','www','yyy')

This query on execution, returns a list of Object[], with each element in the array having an instance each of A,B,C

for example, the result will be as follows

[a1, b1, c11]
[a1, b1, c12]
[a1, b1, c13]

[a2, b2, c21]
[a2, b2, c22]
[a2, b2, c23]

[a3, b3, c31]
[a3, b3, c32]
[a3, b3, c33]

Is there a way to retrieve the result in the following format (using a single EJB QL / HQL query) ?

[a1,b1, set(c1)]
[a2,b2, set(c2)]
[a3,b3, set(c3)]

where, set(c1) will contain objects c11,c12,c13 which are associated to b1 and similarly set(c2) will contain c21,c22,c23 and set(c3) will contain c31,c32,c33

The idea is basically to retrieve a group of associated objects using a single EJB QL /HQL query. Any help or pointers regarding this would help.

Thanks

No, but don't you already have that set in b? If you use "select a, b from A ...", then get the set of Cs as b.getC(), isn't that good enough?

Wouldn't that create an "N+1 selects" problem ?

(Sorry to butt in, but I have a similar pattern in my own code, so I'm curious)

Not in this case, because of the join in the query. C isn't in the select, but it is in the query.

The problem is that I'm trying to store the result sets as a serialized object - i mean storing each object array as a serialized object which will be used later on - like [a1,b1,set(c1)] as a serailized object. So having the results this way would not work out in my case.

Thanks.

Then you'll have to write your serialization code to take account of the fact that the Set<C> is not in ((Object[]) result)[2]), but in ((B)((Object[]) result)[1]).getC().