OLAP stands for Online Analytical Processing, as opposed to OLTP, which stands for Online Transaction Processing. Both are terms from the database world, and as so often happens with computer software abbreviations, there are more letters in the abbreviation than words in the name. One would guess OAP and OTP didn't sound as good to someone. Or perhaps they just couldn't spell.

Broadly speaking, there are two things most organisations want to do with databases: put data in and take summary data out. OLTP is concerned with putting it in, OLAP with taking it out. Oddly enough, the need for OLAP wasn't immediately apparent to the computer programmers who built the first round of databases, leading to huge heaps of data that no one could do anything with.

These days OLAP is associated with a lot of terms like data mining, data warehouses, virtual cubes and data slicing. But what it boils down to is that if your chemist is part of a chain, somewhere there exists a manager with a little application on his computer. And this can tell him exactly how many tubes of a particular brand of shaving cream were bought by male consumers under the age of 42 in the last four months at the same time that they bought condoms.

What the manager will do with this data is another question entirely.