Primary Key in DW and indexes - composite key of all dimensional FKs?
Hi guys,
I have a DW and indexing question. Our metadata DW and physical DW are the same (star schema, no snowflakes). Should all dimensional FKs (such as TIME_KEY, ORG_KEY) be included as a part of a fact table's PK (a composite key becomes a combination of the TIME_KEY, ORG_KEY, etc.) in the database. Second question is, should we create just 1 composite index per fact table (resembling fact table's PK) or should we build several indexes (1 per dimension) ? Also, does it pay to build indexes on dimension tables?
I'm mostly worried about fact table with a few hundred million records that has 7 dimensional-FK columns(only numeric codes), 1 value column, and several ETL-related date columns. I wonder what's the best course scenario be for that one.
Thank you.