OLAP databases are designed and optimized for querying data, typically for reporting purposes.
An OLAP database is usually fed with data from an OLTP database. The data is then organized and aggregated in (multidimensional) cubes rather than tables which allows to analyse the data fast.
There are two fundamental types of data in an OLAP database: measures and dimensions.
The term OLAP was created in 1993 by Edgar F. Codd.
Better performance might be achieved if the data is stored in column format.