doc/book/en/03-definition-schema.en.txt
author Sandrine Ribeau <sandrine.ribeau@logilab.fr>
Mon, 17 Nov 2008 23:54:24 -0800
changeset 95 a5c7609de579
parent 74 9a9fe515934d
permissions -rw-r--r--
[doc] Initial translation of index and introduction for book/en.

.. -*- coding: utf-8 -*-

Data Model definition (*schema*)
================================

The schema is the main concept of `LAX` applications as it defines the
data model we will handle. It is based on entities types already defined
in the library and others, more specific, we would expect to find in one or
more Python files under the `schema` directory.

It is important to make clear the difference between relation type and relation
definition: a relation type is only a relation name with potentially other
additionnal properties (see XXXX), whereas a relation definition is a complete
triplet "<subject entity type> <relation type> <object entity type>". A relation
type could have been implied if none is related to a relation definition of the
schema.


.. include:: 03-sect-stdlib-schemas.en.txt
.. include:: 03-sect-definition-schema.en.txt