Wednesday, September 5, 2012

Day 3_team E_Dhiraj Doley


Online analytical processing



OLAP performs multidimensional analysis of business data and provides the capability for complex calculations, trend analysis, and sophisticated data modelling. OLAP (or Online Analytical Processing) has been growing in popularity due to the increase in data volumes and the recognition of the business value of analytics.

OLAP allows business users to slice and dice data at will. Normally data in an organization is distributed in multiple data sources and are incompatible with each other.

OLAP consists of three basic analytical operations:
  • ·         Consolidation(roll-up)
  • ·         Drill-Down
  • ·         Slicing and Dicing


Multi-dimensional databases generally have hierarchies or formula-based relationships of data within each dimension. Consolidation involves computing all of these data relationships for one or more dimensions, for example, adding up all Departments to get Total Division data. While such relationships are normally summations, any type of computational relationship or formula might be defined. 
Drilling down or up is a specific analytical technique whereby the user navigates among levels of data ranging from the most summarized (up) to the most detailed (down). The drilling paths may be defined by the hierarchies within dimensions or other relationships that may be dynamic within or between dimensions. For example, when viewing sales data for South India, a drill-down operation in the Region dimension would then display Karnataka, Tamil Nadu, and Kerala etc.
Slice is a subset of a multi-dimensional array corresponding to a single value for one or more members of the dimensions not in the subset. The dice operation is a slice on more than two dimensions of a data cube (or more than two consecutive slices).


By,
Dhiraj Kumar Doley
Team E

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