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Business Intelligence




                    Notes          summarized into multidimensional views and hierarchies. By summarizing predicted queries
                                   into multidimensional views prior to run time, OLAP tools provide the benefit of increased
                                   performance over traditional database access tools. Most of the resource-intensive calculation
                                   that is required to summarize the data is done before a query is submitted. This unit on OLAP
                                   explains the concepts and advantages of OLAP, spreadsheet formulas. It also covers study of
                                   metadata.

                                   4.1 Basic Concepts of OLAP


                                   OLAP is a database expertise that has been optimized for querying and describing, rather than
                                   of processing transactions. OLAP data is drawn from historical data, and it is aggregated into
                                   structures that allow complicated analysis. Data in OLAP is also coordinated hierarchically and
                                   placed in cubes instead of tables. It is a sophisticated technology that benefits multidimensional
                                   structures to supply fast access to data for analysis. This association makes it easy for a PivotTable
                                   report or PivotChart report to show high-level abstracts, such as total sales across an entire
                                   region, and also show the details for sites where sales are particularly strong.

                                   OLAP databases contain two basic types of data: measures, which are numeric data, the quantities
                                   and averages that you use to make informed enterprise decisions, and dimensions, which are
                                   the categories that you use to coordinate with these measures. OLAP databases help to coordinate
                                   data by many levels of details by utilizing the identical categories that you are familiar with to
                                   analyse the data.

                                   4.1.1 Components of OLAP
                                                            Figure 4.1: Components of OLAP




















                                   Source:  http://www.esri.com/news/arcuser/0206/graphics/olap_1.jpg
                                   Figure 4.1 shows the components of OLAP
                                   Let us study about them one by one:
                                       Cube: It is a data structure that aggregates the measures by the levels and hierarchies of
                                       each of the dimensions that you want to analyse. Cubes combine some dimensions, such
                                       as time and geography, with summarized data, such as sales or inventory figures.

                                       Measure: It is a set of values in a cube that are founded on a column in the cube’s detail
                                       table and that are generally numeric types. Measures are the centred values in the cube
                                       that are pre-processed, aggregated, and analysed.


                                          Example: sales, earnings and charges




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