diff -r fd8751c3f3ee -r a721966779be doc/book/en/development/datamodel/metadata.rst
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+++ b/doc/book/en/development/datamodel/metadata.rst	Thu May 07 16:33:22 2009 +0200
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+
+Meta-data
+----------
+
+Each entity type has at least the following meta-relations:
+
+eid
+~~~
+Each entity in *CubicWeb* has an associated identifier which is unique
+in an instance. We usually call this identifier `eid`.
+
+`creation_date` and `modification_date`
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Date and time of the creation / lastest modification of an entity.
+
+
+`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.
+
+
+Special relations
+-----------------
+`has_text`
+~~~~~~~~~~
+query the full text index (only for entities having fulltextindexed attributes)
+
+`identity`
+~~~~~~~~~~
+XXX
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