Dynamica SQL

Question

We have created a lot of "MATERIALIZED" views for each parameter values. For example, for parameter A, we would like to use materialized view A. So the final sql would be "SELECT * FROM materialized_view_A".
And for parameter B, we would like to use materialized view B. So the final sql would be "SELECT * FROM materialized_view_B".
This is to improve performance. I can create seperate report for each parameter, but I would like to avoid this otherwise I'll be nightmare to maintain the reports.
Deepak

Answer 1

Hi Rod / Russ
The only time I would use an MV in this situation is if the MV was being created anyway for query performance and there was an index on the item I wanted for the LOV.
In an E-Business Suite environment I always create an MV using the BOM_CALENDAR_DATES, BOM_CAL_WEEK_START_DATES and GL_PERIODS. Here's one of my scripts:
CREATE MATERIALIZED_VIEW DATES_DIM_MV AS
SELECT
GLP.PERIOD_SET_NAME,
BCD.CALENDAR_DATE CDATE,
UPPER(TO_CHAR(BCD.CALENDAR_DATE, 'MON-YY')) CMTH,
'CQ' || TO_CHAR(BCD.CALENDAR_DATE,'YY') || '-' || TO_CHAR(BCD.CALENDAR_DATE, 'Q') CQTR,
TO_NUMBER(TO_CHAR(BCD.CALENDAR_DATE,'YYYY')) CYEAR,
TRUNC (BCD.CALENDAR_DATE,'MM') CMTH_STDATE,
TO_NUMBER(TO_CHAR(BCD.CALENDAR_DATE,'MM')) CMTH_NUM,
TO_NUMBER(TO_CHAR(BCD.CALENDAR_DATE,'DD')) DOM,
UPPER(TO_CHAR(BCD.CALENDAR_DATE, 'MON-YY')) FPERIOD,
SUBSTR('FQ' || DECODE(TO_CHAR(BCD.CALENDAR_DATE, 'Q'), 4,
TO_CHAR(BCD.CALENDAR_DATE + 365,'YY'), TO_CHAR(BCD.CALENDAR_DATE,'YY')) || '-' || DECODE(TO_CHAR(BCD.CALENDAR_DATE, 'Q'), 4,1,3,4,2,3,1,2),1,6) FQTR,
'FY-' || DECODE(TO_CHAR(BCD.CALENDAR_DATE, 'Q'), 4, TO_CHAR(BCD.CALENDAR_DATE+365,'YYYY'), TO_CHAR(BCD.CALENDAR_DATE,'YYYY')) FYEAR,
MOD(TO_NUMBER(TO_CHAR(BCD.CALENDAR_DATE,'MM'))+2,12)+1 FMTH_NUM,
TRUNC(BCD.CALENDAR_DATE,'Q') FQTR_STDATE,
BWS.WEEK_START_DATE WK_STDATE,
BWS.WEEK_START_DATE + 6 WK_ENDATE
FROM
GL.GL_PERIODS GLP,
BOM.BOM_CALENDAR_DATES BCD,
BOM.BOM_CAL_WEEK_START_DATES BWS
WHERE
BCD.CALENDAR_DATE >= '01-OCT-2005' AND
UPPER(GLP.PERIOD_NAME) = UPPER(TO_CHAR(BCD.CALENDAR_DATE, 'Mon-YY')) AND
GLP.PERIOD_SET_NAME = calendar_name1 AND
BCD.CALENDAR_DATE >= BWS.WEEK_START_DATE AND
BCD.CALENDAR_CODE = calendar_name2 AND
BCD.CALENDAR_DATE < BWS.NEXT_DATE AND
BWS.CALENDAR_CODE = BCD.CALENDAR_CODE
ORDER BY 1,2;
Note: replace calendar_name1 and calendar_name2 with whatever is the name of the calendar used by the company. In many cases these are the same value, but some companies have different values.
With that done, I would create a unique indexe on the CDATE, with non-unique indexes on FPERIOD, FQTR, FYEAR and the FWK_STDATE.
I would then use those indexes to create my LOVs.
The above code works for a fiscal calendar that runs from 01-OCT of one year to 30-SEP of the next. The code would need to be adjusted if the fiscal year did not correspond to this.
With this date dimension in place I then replace Oracle's date hierarchies with folders pointing at this MV, with hierarchies on the date, week, month, quarter and year. Performance of most E-Business Suite queries that use GL_PERIOD improve by a factor of between 10 and 100.
Hope this helps
Regards
Michael