<PIVOT and UNPIVOT Operators ⁄ >

I would start with EXCEL spreadsheets to explain what a PIVOT is. In MS Excel 5.0 new functionality was introduced called a 'PivotTable'. Pivot tables are two-dimensional visualization of multidimensional data structures applied in OLAP technology for data warehousing. More correctly say it is two-dimensional sections of three-dimensional OLAP-cubes, if we keep in mind existence of element called "page" on pivot table. You can do common operations with pivot tables under multidimensional structures, for example, mentioned above cube sectioning, consolidation and detail - deconsolidation operation.

It should be said that the pivot table is not a relational, because not only has the column headers, but also has the row headers, while both are formed from data stored in the columns of usual relational tables. It means that numbers of rows and columns is unknown, because they are formed dynamically by querying relational data. In addition, the headers may be multi-level sub-headings that enable the operation of consolidation (move to a higher level of hierarchy) and detail (move to a lower level of the hierarchy).

Such properties allow using pivot tables along with pivot charts in EXCEL as a client to visual displaying of multidimensional data stored in data warehouses that are supported by different DBMS (for example MS SQL Server Analysis Services).



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