|
In this section: |
OLAP reporting requires some preparation both of the data to be reported against and of the report itself. In many instances, this preparation is entirely transparent, having been done before a user encounters an OLAP report. However, for developers who are charged with OLAP-enabling data and reports and for users who wish, and are authorized, to OLAP enable their personal reports, the following summary will be useful.
Behind the scenes of any OLAP report is a hierarchical data structure. For example, a typical hierarchy of sales regions might contain a GEOGRAPHY category including the fields (in descending order) Region, State, and City. Region, the highest level in this hierarchy, would contain a list of all available regions within GEOGRAPHY. State, the second highest level in the hierarchy, would contain a list of all available states within those regions, and others.
In WebFOCUS®, the hierarchical structure is generally built into the Master File for a data source, where it becomes active for any report that uses that data source. Developers or administrators who are responsible for describing data in a Master File can use WebFOCUS language. The keyword WITHIN defines the elements in each dimension in the hierarchy.
In addition to using OLAP-enabled data, a report must be enabled to support OLAP analysis. OLAP-enabling a report consists of specifying how a user will interact with and drill down on OLAP data.
The primary interactions occur in the report itself. In addition, you can choose to expose two supplementary tools, the OLAP Selections panel and the OLAP Control Panel.
The following table describes OLAP terms that may be useful as you work in the OLAP tools. Some of these terms are directly reflected in the interfaces of the OLAP Selections panel and the OLAP Control Panel. Others provide useful background information.
The first column of the following table provides the term and the second column provides the definition.
|
Term |
Definition |
|---|---|
|
Dimension |
Group or list of related elements, usually structured in a hierarchy. For example, a Location dimension could include the elements Country, Region, State, and City arranged in a hierarchy where Country is the top level and City is the base level. Dimensional data usually describes the measured item. |
|
Hierarchy |
Logical parent-child structure of elements within a dimension. |
|
Measure |
Type of item that specifies the quantity of another element with which it is associated. A measure typically defines how much or how many. For example, Units, Revenue, and Gross Margin are measures in the Account dimension and specify how many units were sold, how much revenue was generated, and at what profit margin, respectively. |
|
Pivot |
Manipulating (or rotating) the view of a report by moving a field (or a group of fields) from a column to a row, or row to column. |