Bitmap indexes have effect on query execution and equation of values.

Question

Hi,
I have a Fact table and 17 dimension tables linked to it. On each foreign-key in the Fact-Table I have created a BITMAP Index. After that I Analyzed the fact table and made sure that the referential constraints were valid.
Everything seem to be OK until I ran into a difference in totals when using the next 2 queries that should both result into the same total amount.
Query 1:
Below query is resulting in a wrong total amount and seems to be cartesian.
SELECT    SUM(F.DOLLARS)
FROM       SALES_FACTS         F
,               DIM_TIME                A
,               DIM_CUSTOMER      B
,               DIM_SALESAGENT  C
,               DIM_SALESTYPE     D
,               DIM_GEOGRAFIC     E
WHERE    F.TIME_ID     =     A.TIME_ID
AND         F.CUST_ID     =    B.CUST_ID
AND         F.SA_ID         =    C.SA_ID
AND         F.ST_ID          =   D.ST_ID
AND         F.GEO_ID       =   E.GEO_ID
AND         A.YEAR          =   '2006'
AND         C.SALESNUM =   '3770'
AND D.ST_ID <> '4'
Query 2:
Qeury 2 is the same as query 1 exept the the type of sales (D.ST_ID) is now set with in a range of allowed values. This query gives the correct result.
SELECT    SUM(F.DOLLARS)
FROM       SALES_FACTS         F
,               DIM_TIME                A
,               DIM_CUSTOMER      B
,               DIM_SALESAGENT  C
,               DIM_SALESTYPE     D
,               DIM_GEOGRAFIC     E
WHERE    F.TIME_ID     =     A.TIME_ID
AND         F.CUST_ID     =    B.CUST_ID
AND         F.SA_ID         =    C.SA_ID
AND         F.ST_ID          =   D.ST_ID
AND         F.GEO_ID       =   E.GEO_ID
AND         A.YEAR          =   '2006'
AND         C.SALESNUM =   '3770'
AND D.ST_ID in ('1','2','3','5') In my situation it seems that when I use the <> (not equal to) symbols in combination with the bitmap indexes, that the result of the sum becomes cartesian and thus incorrect.
Has anyone an idea why the calculation of the total amount is different in both queries?
Any help is very appreciated.
Regards, Ilona

Answer 1

Another strange effect is when I leave out the quotation around the not equal to 4 for the Sales_type id (ST_ID <> 4 in stead op ST_ID <> '4' ) then the totals is perfect.
Query 1 version without quotations around ST_ID:
SELECT    SUM(F.DOLLARS)
FROM       SALES_FACTS         F
,               DIM_TIME                A
,               DIM_CUSTOMER      B
,               DIM_SALESAGENT  C
,               DIM_SALESTYPE     D
,               DIM_GEOGRAFIC     E
WHERE    F.TIME_ID     =     A.TIME_ID
AND         F.CUST_ID     =    B.CUST_ID
AND         F.SA_ID         =    C.SA_ID
AND         F.ST_ID          =   D.ST_ID
AND         F.GEO_ID       =   E.GEO_ID
AND         A.YEAR          =   '2006'
AND         C.SALESNUM =   '3770'
AND D.ST_ID <> 4 I still have no clue what causes this effect.
Regards, Ilona