A system to query databases using diagrams as a standard user interface is proposed. The system, called Query by Diagram* (QBD*), makes use of a conceptual data model, a query language on this model, and a graphical user interface. The conceptual model is the entity-relationship model. The query language, whose expressive power allows recursive queries, supports visual interaction. The main characteristics of the interface are ease of use and the availability of a rich set of primitives for schema selection and query formulation. The expressive power of QBD* and G+, which are the only languages allowing recursive queries to be expressed graphically are compared.
QBD*: A graphical query language with recursion / Michele, Angelaccio; Catarci, Tiziana; Santucci, Giuseppe. - In: IEEE TRANSACTIONS ON SOFTWARE ENGINEERING. - ISSN 0098-5589. - 16:10(1990), pp. 1150-1163. [10.1109/32.60295]
QBD*: A graphical query language with recursion
CATARCI, Tiziana;SANTUCCI, Giuseppe
1990
Abstract
A system to query databases using diagrams as a standard user interface is proposed. The system, called Query by Diagram* (QBD*), makes use of a conceptual data model, a query language on this model, and a graphical user interface. The conceptual model is the entity-relationship model. The query language, whose expressive power allows recursive queries, supports visual interaction. The main characteristics of the interface are ease of use and the availability of a rich set of primitives for schema selection and query formulation. The expressive power of QBD* and G+, which are the only languages allowing recursive queries to be expressed graphically are compared.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
