diff -r 76ab3c71aff2 -r c67bcee93248 doc/book/devrepo/datamodel/metadata.rst
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+++ b/doc/book/devrepo/datamodel/metadata.rst	Thu Jan 08 22:11:06 2015 +0100
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+
+Metadata
+--------
+
+.. index::
+   schema: meta-data;
+   schema: eid; creation_date; modification_data; cwuri
+   schema: created_by; owned_by; is; is_instance;
+
+Each entity type in |cubicweb| has at least the following meta-data attributes and relations:
+
+`eid`
+  entity's identifier which is unique in an instance. We usually call this identifier `eid` for historical reason.
+
+`creation_date`
+  Date and time of the creation of the entity.
+
+`modification_date`
+  Date and time of the latest modification of an entity.
+
+`cwuri`
+  Reference URL of the entity, which is not expected to change.
+
+`created_by`
+  Relation to the :ref:`users <CWUser>` who has created the entity
+
+`owned_by`
+  Relation to :ref:`users <CWUser>` whom the entity belongs; usually the creator but not
+  necessary, and it could have multiple owners notably for permission control
+
+`is`
+  Relation to the :ref:`entity type <CWEType>` of which type the entity is.
+
+`is_instance`
+  Relation to the :ref:`entity types <CWEType>` of which type the
+  entity is an instance of.
+