wlrush@water.waterloo.edu (Wenchantress Wench Wendall) (04/21/89)
DEPARTMENT OF COMPUTER SCIENCE
UNIVERSITY OF WATERLOO
SEMINAR ACTIVITIES
MASTER'S ESSAY PRESENTATION
-Thursday, April 27, 1989
Mr. Marc Dionne, graduate student, Dept. of Computer
Science, University of Waterloo will present a Master's
Essay Presentation on ``Optimizing SQL Queries Against
VAX DBMS Databases.''
TIME: 1:30 PM
ROOM: DC 1302
ABSTRACT
The relational model appears to be the state of the art
for current commercially available database products,
but systems based on other models have been widely used
for a number of years. It would be highly desirable to
be able to access these different databases using a
common query language. Given the widespread use of
SQL, it constitutes a good choice for this purpose.
Some form of conversion has to take place between the
user and system levels to allow access to the network
database with a relational query language. We present
the approach used to build an interface between SQL and
a specific network database system, VAX DBMS. From the
DBMS schema we create a relational view of the
database, upon which the user can base his queries.
Given a query, the software generates possible
strategies for evaluation, and determines which one
appears to be the most efficient. This strategy is then
used to evaluate the query, using DBMS data
manipulation commands, and output is produced according
to the specifications of the query.