Web-enabled OLAP Tutorial

- DW Overview

--------Back-end Tools

- Intro to OLAP

--------Codd's 12 Rules

- MD Data Structures

- OLAP Server

- OLAP Operations

- OLAP Architectures

--------MOLAP: Part I
--------MOLAP: Part II
--------ROLAP: Part I
--------ROLAP: Part II

- Data Explosion

- OLAP Criteria

- Glossary

- References

OLAP Operations

One of the most compelling front-end applications for OLAP is a PC spreadsheet program. Below is the list of some popular operations that are supported by the multidimensional spreadsheet applications.


  • Takes the current aggregation level of fact values and does a further aggregation on one or more of the dimensions.
  • Equivalent to doing GROUP BY to this dimension by using attribute hierarchy.
  • Decreases a number of dimensions - removes row headers.

SELECT [attribute list], SUM [attribute names]
FROM [table list]
WHERE [condition list]
GROUP BY [grouping list];


  • Opposite of roll-up.
  • Summarizes data at a lower level of a dimension hierarchy, thereby viewing data in a more specialized level within a dimension.
  • Increases a number of dimensions - adds new headers
Roll-up and Drill-down


  • Performs a selection on one dimension of the given cube, resulting in a sub-cube.
  • Reduces the dimensionality of the cubes.
  • Sets one or more dimensions to specific values and keeps a subset of dimensions for selected values.


  • Define a sub-cube by performing a selection of one or more dimensions.
  • Refers to range select condition on one dimension, or to select condition on more than one dimension.
  • Reduces the number of member values of one or more dimensions.
Dice and Slice

Pivot (or rotate)

  • Rotates the data axis to view the data from different perspectives.
  • Groups data with different dimensions.


  • Accesses more than one fact table that is linked by common dimensions.
  • Combines cubes that share one or more dimensions.


  • Drill down to the bottom level of a data cube down to its back-end relational tables.


  • Spreadsheet style row/column aggregates.