Fixed #3703 -- Added pk property to models. Thanks, Collin Grady and jeromie@gmail.com.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@6346 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/db/models/base.py

@@ -83,6 +83,11 @@ class Model(object):
     def _get_pk_val(self):
         return getattr(self, self._meta.pk.attname)
 
+    def _set_pk_val(self, value):
+        return setattr(self, self._meta.pk.attname, value)
+
+    pk = property(_get_pk_val, _set_pk_val)
+
     def __repr__(self):
         return smart_str(u'<%s: %s>' % (self.__class__.__name__, unicode(self)))
 

docs/model-api.txt

@@ -1284,6 +1284,17 @@ won't add the automatic ``id`` column.
 
 Each model requires exactly one field to have ``primary_key=True``.
 
+The ``pk`` property
+-------------------
+**New in Django development version**
+
+Regardless of whether you define a primary key field yourself, or let Django
+supply one for you, each model will have a property called ``pk``. It behaves
+like a normal attribute on the model, but is actually an alias for whichever
+attribute is the primary key field for the model. You can read and set this
+value, just as you would for any other attribute, and it will update the
+correct field in the model.
+
 Admin options
 =============
 

tests/modeltests/basic/models.py

@@ -33,6 +33,11 @@ __test__ = {'API_TESTS': """
 >>> a.id
 1L
 
+# Models have a pk property that is an alias for the primary key attribute (by
+# default, the 'id' attribute).
+>>> a.pk
+1L
+
 # Access database columns via Python attributes.
 >>> a.headline
 'Area man programs in Python'

tests/modeltests/custom_pk/models.py

@@ -56,6 +56,15 @@ DoesNotExist: Employee matching query does not exist.
 >>> Employee.objects.filter(pk__in=['ABC123','XYZ456'])
 [<Employee: Fran Bones>, <Employee: Dan Jones>]
 
+# The primary key can be accessed via the pk property on the model.
+>>> e = Employee.objects.get(pk='ABC123')
+>>> e.pk
+u'ABC123'
+
+# Or we can use the real attribute name for the primary key:
+>>> e.employee_code
+u'ABC123'
+
 # Fran got married and changed her last name.
 >>> fran = Employee.objects.get(pk='XYZ456')
 >>> fran.last_name = 'Jones'