Joining one tables with two(three?) others

ap46 · **Joined:** Fri Feb 05, 2010 5:49 am **Posts:** 1

Hi, this is my data model:

Code:

[A] 1 --- n [B] 1 --- n [D] n --- 1 [C] n --- 1 [A]

this means: Table A has two 1:n-relations to two other tables (B and C).
Both these tables have a 1:n-relation to the table D.

Another description:
The class A contains a list of Bs and Cs. some of these elemnts in B and C are related like in this table:

Code:

       |    B1  B2  B3  B4
-------+-------------------
  C1   |    X
  C2   |        X   X
  C3   |

B1-4 are entries in table B, C1-3 are entries in table C. Wherever there is an X in the table, there is an entry in table D.

Now I want to fetch all elements of table D which have a relation to elements of B and C which again are related to an entry in table A with a specific primary key.

How can I do the HQL query? I didn't manage to join the tables.

Thank you very much in advance,
AP

Froestel · **Posted:** Fri Feb 05, 2010 12:24 pm

Hi ap46,

looks like you should intersect the results of a query for D restricted by B and A with that of a query for D restricted by C and A. I don't know if HQL supports intersection but SQL does.

CU
Froestel