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Projects archive / The SQLEDDI environment

Title:The SQLEDDI environment
Authors:Meurig Beynon, Michael Evans, Chris Brown, Ashley Ward
Funding:Acad - Academic research
Short description:Studying the design and implementation of SQL
EM Technologies:tkeden, %eden, %scout, %eddi, %toysql, %sqlzero, %sqlte
Keywords:notation, tool, translator, education
empublic references:eddipTruong1996, agentparserBrown2001, sqleddiBeynon2001
EMpress references:
Web site references:,
Previous locations:

This project provides an extension to the tkeden
environment in which it is possible to study the use of SQL in conjunction
with EDDI, a definitive notation based on relational algebra, as a
relational database query language. The design of EDDI is closely based on
that of ISBL (as developed by Todd at IBM Peterlee in 1976). The SQLEDDI
environment can be used to demonstrate the flaws in the design of SQL that
have been identified by commentators such as Date and Darwen, how these
distance it from the underlying relational theory of Codd and introduce
problematic issues in implementation. Further details of relevant
investigations with the model are given in the worksheets and further
documentation cited in the README for the model.

The development of the model originated with the work of Truong in 1996,
who first devised and implemented EDDI using an eden pipeline. This was
later improved by Ward and Beynon. Brown subsequently introduced an EDDI
parser within tkeden to demonstrate the operation of his agent-based parser
in 2001. Much of the work on the sqleddi environment was carried out by
Evans, who implemented the agent-based parser for SQL, and developed the
first prototype for the SQL0 interpreter and SQL-to-EDDI translator. The
current version of the environment was developed by Beynon in conjunction
with a module on Database Systems in October and November 2001, and
improved and modified to work with the new Eden notations framework by
Beynon and Ward in October 2002. [WMB]

sqleddiBeynon2002 is available locally within DCS at /dcs/emp/empublic/projects/sqleddiBeynon2002
Download sqleddiBeynon2002.tar.gz
Uncompressed, sqleddiBeynon2002 is 180.7 Kbytes (in 32 files).
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README 4633 01:04 PM Oct 25 2002 01:19 PM Jul 27 2017
README.xml 2533 05:56 PM Apr 30 2003 01:19 PM Jul 27 2017
README.xml~ 2360 09:26 PM Oct 24 2002 01:19 PM Jul 27 2017
Run1.eden 331 07:26 PM Oct 24 2002 01:19 PM Jul 27 2017
Run2.eden 373 09:27 AM Nov 13 2002 01:19 PM Jul 27 2017
Run2.eden~ 333 09:26 AM Nov 13 2002 01:19 PM Jul 27 2017
Run3.eden 333 03:19 PM Oct 23 2002 01:19 PM Jul 27 2017
Run4.eden 333 03:19 PM Oct 23 2002 01:19 PM Jul 27 2017
fruits.eddi 709 10:38 AM Nov 02 2001 01:19 PM Jul 27 2017
fruits.sql 1471 07:01 PM Oct 24 2002 01:19 PM Jul 27 2017
screenshot.gif 12774 09:31 PM Oct 24 2002 01:19 PM Jul 27 2017
uneddify.scout 3295 12:23 PM Nov 09 2001 01:19 PM Jul 27 2017
SQL0source/ 4096 12:28 PM Oct 25 2002 01:19 PM Jul 27 2017

empublic system initially created by Ashley Ward with assistance from Chris Roe and Meurig Beynon.