diff --git a/gdcdatamodel/models/indexes.py b/gdcdatamodel/models/indexes.py
index 50e4d99e..1344caee 100644
--- a/gdcdatamodel/models/indexes.py
+++ b/gdcdatamodel/models/indexes.py
@@ -62,14 +62,16 @@ def get_secondary_key_indexes(cls):
 
     #: use text_pattern_ops, allows LIKE statements not starting with %
     index_op = 'text_pattern_ops'
-    secondary_keys = {key for pair in cls.__pg_secondary_keys for key in pair}
 
     key_indexes = (
         Index(
             index_name(cls, key),
             cls._props[key].astext.label(key),
             postgresql_ops={key: index_op},
-        ) for key in secondary_keys
+            unique=len(keys) == 1,
+        )
+        for keys in cls.__pg_secondary_keys
+        for key in keys
     )
 
     lower_key_indexes = (
@@ -77,10 +79,25 @@ def get_secondary_key_indexes(cls):
             index_name(cls, key+'_lower'),
             func.lower(cls._props[key].astext).label(key+'_lower'),
             postgresql_ops={key+'_lower': index_op},
-        ) for key in secondary_keys
+        )
+        for keys in cls.__pg_secondary_keys
+        for key in keys
+    )
+
+    # __pg_secondary_keys are "uniqueKeys" in the dictionary yaml file, they are
+    # semantically supposed to be unique locally
+    unique_indexes = (
+        Index(
+            index_name(cls, "_".join(keys) + "_uniq"),
+            *(func.lower(cls._props[key].astext).label(key) for key in keys),
+            postgresql_ops=dict((key, index_op) for key in keys),
+            unique=True  # https://bugs.python.org/issue9232
+        )
+        for keys in cls.__pg_secondary_keys
+        if len(keys) > 1  # skip duplicate indexes
     )
 
-    return tuple(key_indexes) + tuple(lower_key_indexes)
+    return tuple(key_indexes) + tuple(lower_key_indexes) + tuple(unique_indexes)
 
 
 def cls_add_indexes(cls, indexes):
diff --git a/gdcdatamodel/validators/graph_validators.py b/gdcdatamodel/validators/graph_validators.py
index 80748e0f..a8b798d8 100644
--- a/gdcdatamodel/validators/graph_validators.py
+++ b/gdcdatamodel/validators/graph_validators.py
@@ -12,8 +12,7 @@ class GDCGraphValidator(object):
     def __init__(self):
         self.schemas = gdcdictionary
         self.required_validators = {
-            'links_validator': GDCLinksValidator(),
-            'uniqueKeys_validator': GDCUniqueKeysValidator(),
+            'links_validator': GDCLinksValidator()
         }
         self.optional_validators = {}
 
diff --git a/test/test_validators.py b/test/test_validators.py
index 37134f79..5e2e627a 100644
--- a/test/test_validators.py
+++ b/test/test_validators.py
@@ -230,18 +230,3 @@ def test_graph_validator_with_correct_node(self):
                        'target_type': 'sample'}]}])
             self.graph_validator.record_errors(g, self.entities)
             self.assertEquals(0, len(self.entities[0].errors))
-
-    def test_graph_validator_with_existing_unique_keys(self):
-        with g.session_scope() as session:
-            node = self.create_node({'type': 'data_format',
-                                     'props': {'name': 'test'},
-                                     'edges': {}},
-                                    session)
-            node = self.create_node({'type': 'data_format',
-                                     'props': {'name': 'test'},
-                                     'edges': {}},
-                                    session)
-            self.update_schema('data_format', 'uniqueKeys', [['name']])
-            self.entities[0].node = node
-            self.graph_validator.record_errors(g, self.entities)
-            self.assertEquals(['name'], self.entities[0].errors[0]['keys'])