NUL(ID:5340/nul001)

Network database language 

Navigational User's Language
References:
  • Deheneffe , Claude and Hennebert, Henri "NUL: a Navigational User's Language for a network structured data base" view details Abstract: This paper presents an end-user's language which tries to solve the problem of an easy navigation through a DBTG-like data base structure. A request is expressed in a nonprocedural and hierarchically structured fashion. The dialogue is split into two main parts : first a data context definition, then the manipulations of this context.A context is a part of the data base that the user is concerned with. A context definition is formed by a set of labelled lines; each line is a condition declaration on one entity-set. By means of labels and link names declared in the data structure, a line may be connected to another one; this expresses a 'join', by the named link, between the two entity-sets involved in the two lines.The originality of the language lies in the fact that it permits the user to navigate easily and fairly naturally from one entity-set to another through a link; in fact, this navigation is mapped into a hierarchical structure which appears more comprehensible to the user.On the other hand, a manipulation is a command such as print, update, insert or other standard actions the user may want to execute on the context.
          in [ACM SIGMOD/PODS] Proceedings of the 1976 SIGMOD/PODS Conference on Data : Abstraction, definition and structure June 02-04, 1976, Washington, D.C. view details
  • Phillips, Richard L. A query language for a network data base with graphical entities, Proceedings of the 4th annual conference on Computer graphics and interactive techniques, p.179-185, July 20-22, 1977, San Jose, California view details
          in [ACM SIGMOD/PODS] Proceedings of the 1976 SIGMOD/PODS Conference on Data : Abstraction, definition and structure June 02-04, 1976, Washington, D.C. view details
  • Schlageter, G.; Rieskamp, M.; Prädel, U.; Unland, R. "The network query language NOAH" view details Abstract: A non-procedural query language for network databases is described. The language is very powerful as compared to other implemented languages. It allows to formulate complex queries which, among other things, include conditions for CODASYL-sets and conditions for n:m-relationships. Cyclic database structures can be processed to some extent.Note: This report is not written for the "naive" user of NOAH, and is not meant to replace a NOAH manual. Instead, this report describes the foundations, the underlying concepts, and the structure of the language in more theoretically oriented, technical terms.This research was performed at the university of Hagen, West Germany, and was partially supported by Triumph Adler AG, Nürnberg, West Germany. Extract: Description
    NUL is a language which allows the user to navigate from one record set to another one through the sets of the database. The description of NUL is rather brief. NUL seems to allow to process arbitrary search paths and is very flexible in expressing selection conditions. As far as can be seen the language is very powerful as compared to NOAH but the set of queries expressible in NUL is not a real superset of those expressible in NOAH. It has been argued that NUL would not be an easy to use-language. Furthermore, NUL would not be implemented easily in its full generality, especially not on a small system.
          in Proceedings of the 1982 ACM SIGMOD International Conference on Management of Data (Orlando, Florida, June 1982) view details
  • Subieta, Kazimierz "Semantics of query languages for network databases" p.347-394, view details
          in Proceedings of the 1982 ACM SIGMOD International Conference on Management of Data (Orlando, Florida, June 1982) view details