next up previous contents
Next: The model of Up: Squirrel Documentation Previous: SQL

The Extended Data Model (EDM)


The EDM provides the means both for various readings of the lexical items to be expanded, and for some of the different readings to be queries to be ruled-out if they break typing restrictions provided in the database model.

The EDM definition resides in two files. The first is a model of the database containing specifications of:

  1. Domain names.
  2. Tables.
  3. Key fields.

Some of this information is used to rule-out interpretations of the query that do not make sense in the domain.

The second file provides a mapping between expressions in First Order Logic and the Untyped Relational Calculus.

In addition to allowing the translation process, this mapping gives the possibility of expanding various lexical ambiquities.

Chris Fox, September 1995