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.