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SQL join with abstract classes

I'm using GS 6.5 M9 and get error messages like: "java.sql.SQLException: Select failed -1" and "java.sql.SQLException: Select failed null". What I need GS to do is to join two abstract classes and give me ResultSet but it seems impossible to do with GS 6.5 M9. Seems that I can only select variables from leaf node classes in my class hierarchy tree.

Example: "SELECT A.a FROM A, B WHERE A.a = B.aRef" fails (when there is at least one instance of AA in space) whereas query "SELECT AA.a FROM AA, B WHERE AA.a = B.aRef" succeeds.

Same way: "select AA.a, B.b from AA, B where AA.a = B.aRef" fails whereas "select AA.a, BB.b from AA, BB where AA.a = BB.aRef" succeeds

class A { Integer a; }

class AA extends A { Integer aa; }

class B { Integer b; Integer aRef; }

class BB extends B { }

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asked 2008-05-05 07:21:55 -0500

kaarelk gravatar image

updated 2013-08-08 09:52:00 -0500

jaissefsfex gravatar image
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Kaarel,

It is not recommended performing such joins. The cost of such join is relatively large when dealing with large data sets.

Can't you have within the space a Class consolidating data from classes AA and B?

If you queries involves large data set , you might want to perform these from within a business logic co-located with the space and invoke these using the remoting interface. This will avoid passing the result set over the wire and will speed up the overall performance and footprint require to process the query.

If you are looking for such example let me know.

Shay

answered 2008-05-05 18:47:02 -0500

shay hassidim gravatar image
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Asked: 2008-05-05 07:21:55 -0500

Seen: 87 times

Last updated: May 05 '08