Hierarchy in a Dimension - like father/sons

Question

Hello,
I have a standard Oracle rpd model for Service Request (Dim) and Service Request (facts) - that is from OBI Applications.
Facts SR has connection with several other dimensions.
In this customer they have created in the source application (Siebel) an hierarchy in SR, so a parent SR has several child SR.
When modeling this situation in the Warehouse star I did create a new Parent SR Dim connected with a child SR Dim > So I understand this would create a snowflake model.
Now... when trying to query with Answers: Parent SR x Facts >> There are NO records returned.
When querying Child SR x Facts >> OK records returned.
I could eventually create a Fact FK pointing to the Parent SR... but this seems very strange and unorthodox to me.
Would this be a good way of modeling ?
Would it be better to just keep one SR Dim and using Hierarchy Dimension in the rpd try to build the Hierarchy parent x child (like they do in Time dimension f.example) ?
Customer would like to have in a Answer report something like:
Parent - Childs
A X
A Y
A Z
Txs for any hints.
Antonio

Answer 1

Hi Lombo,
I have not worked with SR Modues, but I guess the fact will be of "Accumulating Snapshot Fact" with multiple dates. Choosing SNF to Star totally depends on Business needs and the types of users and data usage.
Creating Parent SR Dim vs SR DIM (with both Parent and Child merger)
1) Cardinality between Parent SR to Child SR. For very high cardinality between Parent SR to Child SR then I would merge Parent with Child.
2) Use snowflake if most of the dimensional data's are sparse, mainly in saving space.
3) Next is the type of users. If you have lots of ad-hoc users who can query against the DB, then ease of use becomes a key desicion maker.
4) Of course you would have to find the optimal balance between space and performance.
And BTW nothing is wrong, in a SQL world I won't say that with SNF i cannot achieve something but can achieve that in Star :).
Regards,
Bharath