It's pretty clear that the term "OLAP" is losing its mojo. In a series of exchanges on Twitter, it was suggested that pivoting is the same as OLAP. I don't agree. Pivot tables were first introduced by Microsoft in Excel over ten years ago (I'm sure someone else used the term prior to that, probably that guy from IBM who invented Business Intelligence in the fifties) J. Other spreadsheet vendors have followed suit. Oracle introduced PIVOT to their non-standard brand of SQL, SQL*Plus, too, but more on that in a minute.
Essentially, a pivot in a spreadsheet is a little more than an a crosstab - transposing columns and rows, with some smarts added in to figure out the unique elements of each identifying "dimension" and performing some rudimentary calculations such as aggregation. It is essentially a linked report, in that changes to the original data are reflected in the pivot table, and this can go both ways.
OLAP, on the other hand, is quite a bit different. It includes:
Multidimensional model at its core: dimensions, hierarchies and attributes
Pivot: the ability to rearrange the display of same without code or script
Drill: at least to drill into detail and drill back up if not across dimensions
Flexible definitions of time
Read &WRITE, though many OLAP tools cannot do the later
Query generation, no coding
This is no the clear definition of pivot tables or "analytics," but Oracle's SQL pivot fails on almost every criterion, especially on no code and fast. That isn't to say it isn't a useful feature in a database, but it's not OLAP and it isn't really pivot, either, which I assume is an interactive process. SQL is not, as far as I'm concerned, interactive.
OLAP as a term may be a little old-fashioned, but it is not the same as pivot tables. However, pivot tables do seem to be on a path to provide all or most of OLAP's functionality.
Interestingly, the energetic wars of ROLAP versus MOLAP of the 90's may have subsided, but OLAP has clearly settled into a cold peace between the two. The true MOLAP's, Essbase. Microsoft, TM1 for example, have settled in for the long haul while the ROLAP's of Microstrategy, SAP Business Objects and Oracle BI have their own adherents and are still viable. Not many people actually use OLAP, perhaps fewer than 10% of the workforce in organizations that own OLAP tools, but it would be reckless to say that OLAP is no longer relevant. If anything, its ascendant thanks to the acquisition of BI vendors by enterprise software companies.
One last thing to consider. Predictive analytics are the topic du jour, but before an analyst builds a predictive model, he/she spends a lot of time profiling the data. A great of this work is done on OLAP tools. In addition, the output from OLAP manipulations is not terribly different from applying models - analyzing data to derive some understanding. And lastly, after predictive models are run, there is a continuing need to examine the results. Fertile ground for OLAP.
Posted December 1, 2009 8:59 PM
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