About collapsible dimensions

Non-root and non-leaf dimension values are collapsible dimensions in a hierarchy.

A collapsible hierarchy is an ordinary hierarchy, in which some or all of the internal (non-root and non-leaf) dimension values are flagged as potentially collapsible. The MDEX Engine automatically removes, or collapses, these dimension values when there are only a few leaves available for refinement, creating a more streamlined, user-friendly navigation experience for your users.

For example, a dimension containing many state names could have a collapsible hierarchy introduced to group the names alphabetically. At query time, the available refinements are determined by the dimension values tagged to the records in the current navigation state. If there are many refinement values, it is easier for a user to select first a letter range, then a letter, and then the state name they want. But if there are only a few values, it is easier for the user to look at a brief list and select the state name directly. In this case, the letter-based dimension values can be collapsed, or removed, so that only the list of state names is displayed.