The purpose of OLAP (On-Line Analytical Processing) is the allow a multidimensional analysis of high-volume databases to conduct a special analysis of data (subjet matter of special querying).
Datamining, other than multidimensional analysis (OLAP), is intended to show any correlations in a significant volume of data of the information system in order to detect any trends.
An EIS (Executive Information System) is a tool which makes it possible to organize, analyze, and determine indicators to create border tables. This type of easy-to-ise tool only makes it possible to handle queries modeled prior thereto by the designer.
A IDSS (Intelligent Decision Support System), in turn, is intended to allow modeling of different and varied multidimensional representations, although it has a steeper learning curve.