HQL; A set-oriented transaction language for hierarchically-structured data bases

The Hierarchic Query Language (HQL) is a sophisticated query language designed to give "non-programmers" convenient access to the data contained within an IMS-like hierarchic data base. In this paper we outline a particular perception of transactions against collections of data arranged in a hierarchic structure, and show how that perception might be reflected in the syntax and semantics of a user-oriented query language.