On-Line Analytical Processing
(OLAP) A category of database software which provides an interface such that users can transform or limit raw data according to user-defined or pre-defined functions, and quickly and interactively examine the results in various dimensions of the data.
OLAP primarily involves aggregating large amounts of diverse data. OLAP can involve millions of data items with complex relationships. Its objective is to analyze these relationships and look for patterns, trends, and exceptions.
Richard Creeth and Nigel Pendse define OLAP as fast analysis of shared multidimensional information. Their definition requires the system to respond to users within about five seconds. It should support logical and statistical processing of results without the user having to program in a 4GL. It should implement all the security requirements for confidentiality and concurrent update locking. The system must provide a multidimensional conceptual view of the data, including full support for multiple hierarchies. Other aspects to consider include data duplication, RAM and disk space requirements, performance, and integration with data warehouses.
Various bodies have attempted to come up with standards for OLAP, including The OLAP Council and the Analytical Solutions Forum (ASF), however, the Microsoft OLE DB for OLAP API is the most widely adopted and has become the de facto standard.
[What's a "multidimensional conceptual view"?]