ERROL, Structured English, Reshaped Relational Algebra (RRA), and The ERROL System

ERROL (initial version) and RRA have been invented by my former graduate student Victor Markowitz. They have been the basis for the ERROL System, developed with grad students. ERROL has constructs similar to those of Natural Language. RRA is used to define accurate and convenient semantics for ERROL. The ERROL System won the 1984 Computer science award by ILA - The Israel Information Technology Organization, and among other places was demonstrated at the demonstration section of the 1987 ACM Conference on Principles of Database Systems (PODS 87) in San Diego.

See   ERROL - Language overview    on this site.

I have taught the course Database systems for several years at the Technion. In the years 1983-6 I also taught ERROL among other database languages and regularly used the query "Find employees that earn more than their managers" to compare expressions in different languages and highlight ERROL's relative convenience.

For RRA I have replaced the original RA operator Subtraction with the operator Not since Subtraction does not have a Natural Language analog convenient construct while Not clearly emulates Natural Language's negation. The operator Not which makes RRA more convenient in the context of Natural Language like languages is defined in the articles  "The Relational Algebraic Operator NOT" and "A Precise Definition of RRA"  below.

ERROL related publications:

Markowitz, Victor M., "ERROL: An Entity Relationship Role Oriented Query Language, M.Sc. Thesis, Dept. of Computer Science, Technion, Haifa, Israel (January 1983).

V.M. Markowitz, Y. Raz, "The Semantics of ERROL", CS Dept. Technion, Haifa, TR #279, June 1983. 

Markowitz, V.M. and Raz, Y.: "ERROL - An Entity Relationship Role Oriented Query Language", In Entity Relationship Approach to Software Engineering, October 5-9, 1983, Anaheim, California. Davis, G.C. et al. (eds.), pp. 329-345, North- Holland, 1983.

Markowitz, V.M. and Raz, Y.: "A Modified Relational Algebra and Its Use in an Entity Relationship Environment", In Entity Relationship Approach to Software Engineering, October 5-9, 1983, Anaheim, California. Davis, G. C. et al. (eds.), pp. 315-328, North-Holland, 1983.

Alperstein, Varda, "An Entity Relationship Interface for the INGRES DBMS", M.Sc. Thesis, Dept. of Computer Science. Technion, Haifa, Israel (March 1984).

V. M. Markowitz and Y. Raz: "An Entity-Relationship Algebra and its Semantic Description Capabilities", J. Sys. and Soft., Vol.4, No.2, pp. 147-162 , 1984.

Yoav Raz, Reuven Cohen, Victor M. Markowitz: ERROL - An Entity Relationship, Role Oriented Query and Data Manipulation Language (Extended abstract), The 9th National Conference on Data Processing together with the 4th Jerusalem Conference on Information Technology (JCIT4), May 21-25, 1984, Jerusalem. (ILA award in Computer Science for the ERROL System.)

Cohen, Reuven, "The Translation of ERROL to RRA -A Reshaped Relational Algebra," M.Sc. Thesis, Dept. of Computer Science, Technion, Haifa, Israel (July 1984). 

Ofer Imanuel, Yoav Raz: "The ERROL System", CS Dept. Technion, Haifa, TR #411, 1986.

Yoav Raz: "The Relational Algebraic Operator NOT"CS Dept. Technion, Haifa, TR #421, 1986.

D. Steinberg, Y. Raz, E. Kantorowitz: "Translating ERROL, a High Level, ER, Structured English Language, for DBTG Databases", (extended abstract), In the Proc of the 6th Int. Conf. on the Entity-Relationship Approach, pp. 337-360, New York City, Nov. 9-11, 1987.  (Graduate student M.Sc. project)

Y. Raz : "The ERROL System Version 2.0 - An Overview", EECS Dept. UCSD, 1987.    (Were ERROL syntax was relaxed considerably to make it closer to NL)


RRA rephrased, with ERROL System examples. Originally TR #405, Technion, Israel, March 1986.

Yoav Raz: A Precise Definition of RRA - a Reshaped Relational Algebra which Follows Natural Language Constructs (pdf)


ERROL, translation to RRA using hypertrees, and ERROL System examples. TR CS-093, EECS Dept., University of California at San Diego (UCSD), 1987. Previous version appeared as "Supporting Natural Language Interfaces for Relational Databases Using RRA", TR # 410, Technion, Israel, May 1986. "Natural Language" appeared to be problematic to some NL reviewers, and title was changed... (one reviewer wrote: "ERROL is as ugly as COBOL and SQL" ; This is a ridiculous comparison, since in ERROL NL-like expressions are predicates from the application domain, not commands, parts of the programming language, as in COBOL and SQL)

Yoav Raz: Supporting Structured English Interfaces for Relational Databases Using RRA (pdf)

Was accepted to a journal (DKE; by Peter Chen) in 1988 subject to literature review update, but this has been delayed due to busy relocation, and never sent (sorry, Peter).


The ERROL System team members:

Victor Markowitz, Reuven Cohen, Varda Alperstein, Ofer Imanuel, Doron Steinberg, Dan Jones, and Susan Gruber.



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