Star transformation prerequisites

Oracle version 9.2.0.6 Enterprise Edition Solaris 2.8

Can someone please definitively clarify if it is mandatory for foreign keys (not necessarily enabled) to be declared, in order that that CBO will apply star transformation in a traditional star schema? (fact table and dimension tables are indexed according to Bert Scalzo's Guide to Oracle 8i Data Warehousing). In the Bert Scalzo book I did not see a categorical statement that the fks MUST be declared.

In the Oracle 9.2 Data warehousing guide, I also cannot find where it is clearly stated that the fks MUST be declared, only that the fks (join columns) must have bitmap indexes (subtle difference).

I have also read Jonathan Lewis's various articles on bitmap indexes and can find nothing clear there either.

star_transformation_enabled = temp_disable

# As I recall (from a year ago), hit a bug in 9.2.0.4 where use of temp tables had serious negative impact on some queries. Never turned it back to value = "true"

My questions are:
1. Are foreign key declarations mandatory for the CBO to use star transformation, if fks are not declared, but the bitmap indexes exist and all objects are appropriately analyzed?

2. Do fks influence the CBO? If so, how? Can someone point me at or recommend documentation?

I posted the same question on the Metalink forum, and the only response so far has been from someone who has NOT declared fks but has observed star transformation, (but no explain plans or schema descriptions were given).

If this is a case of me misreading documentation, I apologize.

thanks

Tim Brown
PCS Technology Group
JPMChase

tim.x.brown_at_jpmchase.com
(614) 213-9259
(614) 226-8605

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