[ont.events] DATABASE/MASTER'ESSAY PRESENTATION/SEMINAR

daemon@watdragon.waterloo.edu (Owner of Many System Processes) (06/28/89)

``Parsing and Semantic Analysis of SQL/W.''
From: wlrush@poppy.waterloo.edu (Wenchantress Wench Wendall)
Path: poppy!wlrush



DEPARTMENT OF COMPUTER SCIENCE
UNIVERSITY OF WATERLOO
SEMINAR ACTIVITIES

DATABASE/MASTER'S ESSAY SEMINAR

                    -Tuesday, July 4, 1989

Danny   Zilio,  graduate  student,  Dept.  of  Computer
Science, University of Waterloo, will speak on 
``Parsing and Semantic Analysis of SQL/W.''

TIME:                 10:00 a.m.

ROOM:              DC 1304

ABSTRACT

SQL/W  is  the  query language for the LauRel prototype
database  system  being  developed  at  Waterloo.  This
language  is  based  on SQL with the added extension to
nested   relations.    Set-valued   attributes  (nested
relations)  and reference attributes (pointers, foreign
keys)  are used in the data model. The basic query form
is:

select <attribute list>
from <relation variables>
where <query predicate>

The  attributes in the ``attribute list'' can either be
atomic   attributes   or   complex   attributes,   i.e.
attributes  built  from  relational-valued  attributes.
The  relation  variables  are  relation  names  and the
predicate  is  a  condition  determining  which  tuples
should  be  included  in the answer, which is output in
the  format  given  in the ``select'' line.  The syntax
was  created to be orthogonal which means that whenever
an  attribute  can occur in a query, by the same token,
another  ``nested''  query  can  be  placed in the same
position.  This allows operations on nested relations.

The  compiler  for SQL/W has two components.  The first
consists  of  the  parser  and  resides  on any machine
operating UNIX and SOCKETS.  The second consists of the
semantic   analyzer,   the  dictionary  and  all  other
functions  included in the LauRel project.  This second
component  resides  on the SEQUENT and makes use of the
parallel micro-kernel developed by Rick Stroobosscher.

The  talk  will discuss the syntax and semantics of the
SQL/W language and will describe an implementation of a
parser and semantic analyzer for the language.