SQL/N AND MODES OF ASSOCIATION IN BILL OF MATERIALS DATA BASESIN MANUFACTURING AND ENGINEERING DESIGN
Abstract
An idealized bill of materials data base is presented for the part types
used in complex engineering creations. Central to such a data base is a
recursive many-to-many association. It is shown how useful modes of
association can be defined for the one-to-many associations of the
data base and for that part of the recursive association involving any two
levels of teh part type hierarchy implicit in such a data base. It is
shown that SQL/N can then be used to manipulate the data base using
these modes of association and natural quantifiers. The SQL/N expressions all
follow the structure of corresponding English-language expressions,
whereas conventional SQL expressions do not. Not covered in the report is
the case of modes of association for that part of the recursive association
that deals with large and unpredictable number of levels of the part type
hierarchy.
Description
Keywords
Computer Science