Joao E.S. Pacheco's scientific contributions

Publications (3)

Technical Report
Full-text available
A Functional Model of Data is presented as a labelled pseudo-graph whose nodes are sets and whose arcs are total functions. The model allows one to represent partial functions, binary relations, n-ary relations, as well as m-ary associations among relations. Injective functions play the role of candidate keys. Graph algorithms transform the model...
Conference Paper
Synthetic English is a very-high-level query language based on natural English. Query specification in Synthetic English parallels the user's natural thought processes, thereby allowing him to formulate complex queries without regard to implicit or explicit language control structures. Synthetic English is designed to be used in conjunction with th...

Citations

... Data models have been used in information engineering environments for many decades for the precise purpose of building representations of reality. To date, there have been many different data modelling languages proposed with the most popular being the Entity-Relationship Model (Chen, 1976) but also including the Functional Data Model (Kerschberg & Pacheco, 1976;Shipman, 1981), the Semantic Data Model (Hammer & McLeod, 1981), NIAM (Nijssen & Halpin, 1989), and Object Modelling Technique (Blaha & Premerlani, 1998). Each new modelling language has often been accompanied with claims of its superiority and at times hype when compared with the others. ...
... In particular, a COM query may well produce a function (by processing data in other functions) rather than a set. The idea of using functions for data modeling is not new and this branch has a long history of research starting from [6,16]. COM can be viewed as a further development of the functional data modeling paradigm. ...
... A flexible and a high-level query language called SYN- GLISH, based on natural English for use in conjunction with the functional data model (which is a conceptual graph model), which is transformable to the relational model, has been designed. SYNGLISH has been claimed to be superior to the other existing relational languages in terms of the ease with which a casual user could formulate complex queries [Kerschberg 1976b]. It has been designed for use with the Relational Associative Processor (which is described in the section on Data Base Machines). ...