Added support for compound primary keys (#149)

AUTHORS

@@ -136,3 +136,4 @@ that much better:
  * Aleksey Porfirov
  * Nicolas Trippar
  * Manuel Hermann
+ * Gustavo Gawryszewski

docs/changelog.rst

@@ -37,6 +37,7 @@ Changes in 0.8.X
 - Added no_dereference context manager (#82)
 - Added switch_collection context manager (#220)
 - Added switch_collection method to document instances (#220)
+- Added support for compound primary keys (#149)
 
 Changes in 0.7.9
 ================

docs/guide/defining-documents.rst

@@ -135,7 +135,8 @@ arguments can be set on all fields:
     field, will not have two documents in the collection with the same value.
 
 :attr:`primary_key` (Default: False)
-    When True, use this field as a primary key for the collection.
+    When True, use this field as a primary key for the collection.  `DictField`
+    and `EmbeddedDocuments` both support being the primary key for a document.
 
 :attr:`choices` (Default: None)
     An iterable (e.g. a list or tuple) of choices to which the value of this
@@ -441,6 +442,7 @@ The following example shows a :class:`Log` document that will be limited to
 
 Indexes
 =======
+
 You can specify indexes on collections to make querying faster. This is done
 by creating a list of index specifications called :attr:`indexes` in the
 :attr:`~mongoengine.Document.meta` dictionary, where an index specification may
@@ -475,18 +477,20 @@ If a dictionary is passed then the following options are available:
 
 .. note::
 
-    To index embedded files / dictionary fields use 'dot' notation eg:
-    `rank.title`
+    Inheritance adds extra fields indices see: :ref:`document-inheritance`.
 
-.. warning::
+Compound Indexes and Indexing sub documents
+-------------------------------------------
 
-    Inheritance adds extra indices.
-    If don't need inheritance for a document turn inheritance off -
-    see :ref:`document-inheritance`.
+Compound indexes can be created by adding the Embedded field or dictionary
+field name to the index definition.
 
+Sometimes its more efficient to index parts of Embeedded / dictionary fields,
+in this case use 'dot' notation to identify the value to index eg: `rank.title`
 
 Geospatial indexes
----------------------------
+------------------
+
 Geospatial indexes will be automatically created for all
 :class:`~mongoengine.GeoPointField`\ s
 

tests/document/indexes.py

@@ -693,5 +693,39 @@ class IndexesTest(unittest.TestCase):
         index_item = [('_id', 1), ('comments.comment_id', 1)]
         self.assertTrue(index_item in info)
 
+    def test_compound_key_embedded(self):
+
+        class CompoundKey(EmbeddedDocument):
+            name = StringField(required=True)
+            term = StringField(required=True)
+
+        class Report(Document):
+            key = EmbeddedDocumentField(CompoundKey, primary_key=True)
+            text = StringField()
+
+        Report.drop_collection()
+
+        my_key = CompoundKey(name="n", term="ok")
+        report = Report(text="OK", key=my_key).save()
+
+        self.assertEqual({'text': 'OK', '_id': {'term': 'ok', 'name': 'n'}},
+                         report.to_mongo())
+        self.assertEqual(report, Report.objects.get(pk=my_key))
+
+    def test_compound_key_dictfield(self):
+
+        class Report(Document):
+            key = DictField(primary_key=True)
+            text = StringField()
+
+        Report.drop_collection()
+
+        my_key = {"name": "n", "term": "ok"}
+        report = Report(text="OK", key=my_key).save()
+
+        self.assertEqual({'text': 'OK', '_id': {'term': 'ok', 'name': 'n'}},
+                         report.to_mongo())
+        self.assertEqual(report, Report.objects.get(pk=my_key))
+
 if __name__ == '__main__':
     unittest.main()