At the same time, the ProDataSet is made up of mostly familiar components, in particular temp-tables, which you use to define the data at a particular level of the business object the ProDataSet represents. In this way, this powerful new tool can build on the strength of existing ABL components and existing procedural code while extending it in new ways.
The ProDataSet can be thought of as an "in-memory database" in the sense that it is filled with a set of related records in potentially multiple temp-tables that can then be traversed in a predictable way, and also passed as a single parameter from procedure to procedure or session to session with all the data being passed together.