How to understand the way OBIEE implements outer joins?

Question

Hello guys
I have a few scenarios where I have to implement outer joins and inner joins between dimensions and facts..
There are 2 ways as far as I know that allows me to implement outer joins in BMM layer.
1, Join the Logical dim table A to Logical Fact table B using outer join. The modeling will look like the below:
A Dim ---outer------B fact -----------inner----C Dim
By this design, the query that selects columns from all 3 tables will look at this:
select columns from ((B fact inner joins C on key1 = key2) left outer joins on A dim) on key3=key4)..
2, Join logical dim table A to fact table B inside the LTS of fact B by mapping the LTS B to dim A using outer join. then join fact B to C:
B fact (mapped to fact B outer join Dim A) ------------inner -------C dim
By this design, the query that selects columns from all 3 tables will look at this instead:
select columns from C, B left outer join A on key1=key2 where key3=key4
Comparing these 2 queries, the first one seems to do inner joins first and then outer join the result set to Dim A, the second query seems to outer join Dim A first and the result set inner joins to Dim C..
I ran the same report using these 2 different designs, and the data comes out very different. The report of the first query is much smaller than the report of the second query...
Can anyone help me understand how OBIEE understands outer joins? The second query is so far giving the right result, however, I can't get rid of the outer join in the query even if not selecting columns from Dim A, which is impacting the performance of other reports without Dim A.
Your inputs will be greatly appreciated
Thanks
Edited by: user7276913 on Apr 20, 2010 9:31 AM
Edited by: user7276913 on Apr 20, 2010 9:31 AM

Answer 1

Xcode is the IDE.
Objective-C is the language typically used.
There's lots of getting started stuff at https://developer.apple.com