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Graphical Query Facility for a Relational Database

IP.com Disclosure Number: IPCOM000102602D
Original Publication Date: 1990-Dec-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 2 page(s) / 70K

Publishing Venue

IBM

Related People

Burns, L: AUTHOR [+2]

Abstract

Disclosed is a design for the graphical representation of a relational database schema and the specification of queries on the schema graph. This approach is different from the state of the art (METAPHOR*) as the user explicitly selects the query path rather than the path being computed for the user based upon the projected columns.

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Graphical Query Facility for a Relational Database

       Disclosed is a design for the graphical representation of
a relational database schema and the specification of queries on the
schema graph.  This approach is different from the state of the art
(METAPHOR*) as the user explicitly selects the query path rather than
the path being computed for the user based upon the projected
columns.

      In the METAPHOR product (prior state of the art) the following
steps are required to specify a query.
  The user selects the columns to be projected from a list of the
tables in the database and their columns. (Note: list of tables and
columns rather than schema graph.)
  METAPHOR determines the joins required to generate the query by
selecting from a set of predefined joins.
  The system displays a graph of the tables and the joins.
  The user specifies constraints on the tables and other information
to complete the query specification.

      Some important limitations of the METAPHOR approach are:
  Some of the predefined joins are automatically generated by
matching columns with identical names in different tables.
Additional joins can be added by the System Administrator but not by
the end-user.
  The attempt to determine the joins based on the projected columns
can result in ambiguous paths.  Consider a database with tables
Person, Bank, Account and Loan.  If the user requests a query with
Person.Name and Bank.Name as the projected columns, two paths are
possible as shown in the figure.  METAPHOR attempts to conceal the
joins from the user.  In a situation where the path...