Data Modelling for Data Warehousing

Wednesday, January 27, 2010

Overview
Data Cubes = A data which are available in multidimensional matrices is called Data Cubes.
· A excel sheet is a two dimensional matrix, it can have sales revenue of corresponding geographical regions.
· Change process of converting one dimensional to another in the data cube is called pivoting.
• In pivoting, the data cube can rotate to see the data in different orientation.
• So, this technique is equivalent to product sales table by region.
• There are two kinds of Hierarchical views of multidimensional models:
1. Roll-up display
In the Roll-up display the hierarchy will move up and it will group into the larger units.
E.g.: Weekly data summation by quarter and by then by year.
2. Drill-down display
In the Drill-down display it will have opposite view.
E.g. dividing the region sales into sub-region and then again dividing sub-region sales country specific sales.