OLAP

=Online Analytical Processing (OLAP)= Tuesday, April 8

Topic overview:
//Online Analytical Processing (OLAP) tools// can be thought of as a special type of reporting tool. OLAP tools are highly optimized for rapid, interactive exploration of dimensional data. By representing dimensional data as 'hypercubes', OLAP tools can perform many complex queries over enormous data sets orders of magnitude faster than a comparable relational database. SQL Server 2005's OLAP tools are called //Analysis Services//.

We will use Analysis Services in class and (optionally) in assignment #2 to explore and analyze large, complex data sets.

Specific topics that we will cover include:
 * Understanding the role of OLAP tools in a BI program
 * Dimensional modeling and OLAP Hypercubes (facts, measures, dimensions, and levels)
 * Analyzing data with OLAP tools

**Preparation for class:**
Prior to class, please download and read the following overview of dimensional modeling:
 * [PJ01] Pedersen, Torben Bach and Jensen, Christian S., "Mutidimensional Database Technology", IEEE Computer, December 2001, pages 40-46. http://infolab.usc.edu/csci599/Fall2002/paper/I1_pederson_p40.pdf

We will be using an online set of OLAP demos in class from a company called Contour Components. In order to run these demos on your machine you will need to be running Internet Explorer 6.0 or higher, and to have installed a set of ActiveX components from the Contour Components website. You will be able to do this in class, but it takes a few minutes to do so. To make sure that you can follow along in class, and to give you a bit of a flavor of how OLAP works prior to class, please do the following steps prior to Tuesday's class:


 * Open http://olaplib.contourcomponents.com/ in Internet Explorer 6.0 or higher
 * Ok the installation of any ActiveX controls that the site requests
 * Use the Samples > menu in the upper left of the screen to open up any sample OLAP cube that interests you.
 * Again, ok the installation of any requested ActiveX controls that the site requests
 * Explore the data presented in the cube and see if you can interepret it and find anything interesting in it

Installation of the ActiveX controls is not required for the class but they will probably help you significantly in understanding OLAP. I can provide little or no tech support to get them to run on your machine but it should take less than 10 minutes to do the install and will likely make it much easier for you to participate in the in-class examples on Tuesday.