--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/doc/book/en/03-definition-schema.en.txt	Fri Nov 14 11:05:32 2008 +0100
@@ -0,0 +1,20 @@
+.. -*- 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