This topic uses the DM Query, Short Drinks, and Household samples that come with the UNICOM Intelligence Developer Documentation Library to demonstrate how HDATA hierarchical virtual tables work. Before working through the exercises in this topic, read Hierarchical data in the MDM, which provides an introduction to the metadata structures that are used to collect hierarchical data and how they map to columns and tables in the case data.

Although both versions of DM Query provide support for hierarchical data, it is better in the Visual Basic 6 version of DM Query. The instructions and screenshots in this topic refer to the Visual Basic 6 version of DM Query.