Squirrel Documentation

Chris Fox

September 1995

A postscript version of this documentation is also available.

Note: comments on this documentation or questions about Squirrel should be addressed to the author at Essex University, email: foxcj@essex.ac.uk. You may also contact the author if you wish to be informed of substantial updates to this document, or the online demonstrator.

Abstract:

This documentation outlines what the system does, the representations it uses, and gives an indication of the systems coverage. Currently, it is intended to give a flavour of how the system works, rather than the sort of detail needed to reconstruct the programs or configure them for a new domain.

• Contents
• Overview of Squirrel
• Squirrel's Grammar and lexicon
  • The Grammar
  • The Lexicon
  • Compiling the grammar and lexicon
• Stages of Translation
  • Property Theory (PT)
    • Formal Definition of PT terms
  • First order logic (FOL)
    • Formal Definition of FOL
  • Untyped Relational Calculus (URC)
    • Formal Definition of URC
  • Domain Relational Calculus (DRC)
    • Formal Definition of DRC
  • First Optimisation (OP1)
  • Tuple Relational Calculus (TRC)
    • Formal Definition of TRC
  • Second Optimisation (OP2)
  • Third Optimisation (OP3)
  • SQL
• The Extended Data Model (EDM)
  • The model of the database
  • Mapping Information
• Sample Runs
  • Simple Queries
    • Edna earns which salary?
    • Which employee earns more than 2000?
    • Which dept is on which floor?
    • Who is older than Edna's manager?
    • Who works for a salary that is greater than 2500?
    • Which dept has an employee that is managed by Malcolm?
  • Examples with the Paraphraser
    • Who earns more than 2500?
    • Who works for what?
    • Which manager works in admin?
    • What is Edna's salary?
  • Examples of Modal Queries
    • Can Edna earn 2000?
    • Can Edna earn 234?
    • Can Sally work in food?
    • Can an employee work in admin and be 34?
• Prototype Form
• About this document