Fixed #8533: restored model inheritance docs, and updated one-to-one docs to match

git-svn-id: http://code.djangoproject.com/svn/django/trunk@8757 bcc190cf-cafb-0310-a4f2-bffc1f526a37

docs/ref/models/fields.txt

@@ -811,7 +811,10 @@ define the details of how the relation works.
 
     The name to use for the relation from the related object back to this one.
     See the :ref:`related objects documentation <backwards-related-objects>` for
-    a full explanation and example.
+    a full explanation and example. Note that you must set this value
+    when defining relations on :ref:`abstract models
+    <abstract-base-classes>`; and when you do so
+    :ref:`some special syntax <abstract-related-name>` is available.
 
 .. attribute:: ForeignKey.to_field
 
@@ -883,8 +886,27 @@ that control how the relationship functions.
 ``OneToOneField``
 -----------------
 
-.. class:: OneToOneField(othermodel, [**options])
+.. class:: OneToOneField(othermodel, [parent_link=False, **options])
 
-The semantics of one-to-one relationships will be changing soon, so we don't
-recommend you use them. If that doesn't scare you away, however,
-:class:`OneToOneField` takes the same options that :class:`ForeignKey` does.
+A one-to-one relationship. Conceptually, this is similar to a
+:class:`ForeignKey` with :attr:`unique=True <Field.unique>`, but the
+"reverse" side of the relation will directly return a single object.
+
+This is most useful as the primary key of a model which "extends"
+another model in some way; :ref:`multi-table-inheritance` is
+implemented by adding an implicit one-to-one relation from the child
+model to the parent model, for example.
+
+One positional argument is required: the class to which the model will
+be related.
+
+Additionally, ``OneToOneField`` accepts all of the extra arguments
+accepted by :class:`ForeignKey`, plus one extra argument:
+
+.. attribute: OneToOneField.parent_link
+
+    When ``True`` and used in a model which inherits from another
+    (concrete) model, indicates that this field should be used as the
+    link back to the parent class, rather than the extra
+    ``OneToOneField`` which would normally be implicitly created by
+    subclassing.

docs/ref/models/options.txt

@@ -4,13 +4,21 @@
 Model ``Meta`` options
 ======================
 
-This document explains all the possible :ref:`metadata options <meta-options>` that you can give your model in its internal ``class Meta``.
+This document explains all the possible :ref:`metadata options <meta-options>`  that you can give your model in its internal
+``class Meta``.
 
 Available ``Meta`` options
 ==========================
 
 .. currentmodule:: django.db.models
 
+``abstract``
+------------
+
+.. attribute:: Options.abstract
+
+If ``True``, this model will be an :ref:`abstract base class <abstract-base-classes>`.
+
 ``db_table``
 ------------