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Data Mining Query Language

Data Mining Query Language (DMQL) can be used to extract the information we require. There are 2 language primitives in defining a data warehouse. One for cube definition and one for dimensions definition. the DMQL structure is as follows:

Define cube (cube_name)[(dimension_list)]:(measure_list)

Define dimension (dimension_name) as ((attribute_or_subdimension_list))

OLAP operations in the multidimensional data model:

each dimension contains multiple levels of abstraction defined by concept hierarchies

this allows the user to view data from different perspectives

OLAP operation:

Roll-up - perform aggregation on a data cube by climbing up a concept hierarchy

Drill-down - reverse of roll-up

slice - selects on one dimension of the cube, results in a sub cube

dice - selects on 2 dimensions of a cube

pivot - rotates data axes for alternate visual presentation

Information on this page are based on Data Mining & Datawarehousing, Farhad Daneshgar, 2001.