Drill Down Till You Drop: OLAP Without Windows - NESUG

defined in the drill down hierarchy, the spacerequired to store the data is even less that if the rawoutput from PROC SUMMARY is used.• Flexibility - Since the summarized data is derivedfrom the detail data, any additional variables canquickly be added to the summary data set withoutsignificant impact of speed, or size. Additionally,there is no need to go through multiple levels of drilldown, if you directly specify which level you want toprocess. Multiple Drill downs hierarchies can bedefined, with defined cross-dimension capabilities.Author ContactRalph WintersAlydon Technical Services, Inc.20 Essex Rd, Suite 2AMaplewood, NJ 07040973-275-6248ralph_winters@internetmci.com• New drill hierarchies can be prototyped using thismethod before they are introduced into applications.Summary data sets created by this method can bequeried directly by AF applications, saving the needto develop separate data structures.• Ability to easily combine dimensions of differenttypes into one drill hierarchy. No need to establishseparate dimension tables.Disadvantages• Need to run PROC SUMMARY every time theunderlying data changes.• Knowledge of the value of the _TYPE_ value isrequired at all time. This can be overcome by usingmacro techniques and assigning symbolic names.• The optimized summary dataset is only meaningfulwith respect to the drill down hierarchy. If the drilldown hierarchy is not used, or is restrictive in anyway, it does not make sense to use this technique.ReferencesCodd, E.F., Codd S.B., Salley C.T. (1993), “ProvidingOLAP (On-Line Analytical Processing) to User-Analysts:An IT Mandate”SAS Institute Inc. (1990) SAS ® Procedures Guide,Version 6, Third Edition, Cary, NC: SAS Institute, Inc.SAS, SAS/AF, SAS/EIS are registered trademarks of SASInstitute Inc. in the USA and other countries. ® indicatesUSA registration.Other brand and product names are registered trademarksor trademarks of their respective companies.10