Hierarchies for regular dimensions

A hierarchy is an ordered list of levels or a collection of items. Each query item in a hierarchy must have a unique name.

You can specify multiple hierarchies on regular dimensions in IBM® Cognos® Framework Manager. Multiple hierarchies for a regular dimension behave as views of the same query. The first hierarchy is the primary or default hierarchy.

You can use only one hierarchy at a time in a query. For example, you cannot use one hierarchy in the rows of a crosstab report and another hierarchy from the same dimension in the columns. If you need both hierarchies in the same report, you must create two dimensions, one for each hierarchy. For more information, see Modeling dimensions with multiple hierarchies.

For example, sales staff can be viewed by manager or by sales branch and can be modeled as a single dimension with two hierarchies.

Example of a single staff dimension

If you need both hierarchies in the same report query, such as on opposing axes, you must create a regular dimension for each hierarchy. For example, here is sales staff as two dimensions.

Example of two staff dimensions

To change the default hierarchy for a dimension with multiple hierarchies, in the Properties pane, click the ellipsis (...) button in the Default Hierarchy box, and select a different hierarchy.

If a hierarchy in a dimension contains a large number of members, running a query in one of the IBM Cognos studios may be slow because the IBM Cognos engine is generating one large query for a locally-built cube. To resolve this issue, set the Wide Member Tree property in the Properties pane to true. The engine will then generate multiple smaller queries for the locally-built cube.