Drill down
As drill down (or drill-down ) is generally the navigation in hierarchical data referred.
In Online Analytical Processing (OLAP) and Information Retrieval , drilldown is a process in which the various properties of existing information objects are used in order to gradually refine the analysis or search for them. In OLAP, the properties are called dimensions . In information retrieval, however, one speaks of facets . Drilldown enables you to “zoom in”, in which the existing data can be viewed in different levels of detail. The opposite viewing direction, a step-by-step “zooming out”, is called roll-up or drill-up.
Examples
- A company's sales are stored in a data warehouse with information on the period, product line and branch and can be summarized and evaluated according to each of these dimensions.
- A digital product catalog in an online shop contains data records on various digital cameras with information on price class, resolution and manufacturer. If you select a manufacturer, the amount of data records is limited to this one. The remaining data sets can be searched by price class and resolution. The amount of data records can also be further limited by further selecting a group.
Dimensions and Classifications
The various dimensions can in turn be further subdivided hierarchically . For example, in the company example, the branches can be grouped by continent and country. In data warehousing, such a subdivision is called a classification hierarchy. In information retrieval, a facet classification is divided into different classifications for each individual facet.