Allow for disconnected tables

sdv/metadata/multi_table.py

@@ -513,14 +513,6 @@ def _detect_relationships(self):
                                            sdtype=original_foreign_key_sdtype)
                         continue
 
-        try:
-            self._validate_all_tables_connected(self._get_parent_map(), self._get_child_map())
-        except InvalidMetadataError as invalid_error:
-            warning_msg = (
-                f'Could not automatically add relationships for all tables. {str(invalid_error)}'
-            )
-            warnings.warn(warning_msg)
-
     def detect_table_from_dataframe(self, table_name, data):
         """Detect the metadata for a table from a dataframe.
 
@@ -739,14 +731,10 @@ def validate(self):
         for relation in self.relationships:
             self._append_relationships_errors(errors, self._validate_relationship, **relation)
 
-        parent_map = self._get_parent_map()
         child_map = self._get_child_map()
 
         self._append_relationships_errors(
             errors, self._validate_child_map_circular_relationship, child_map)
-        self._append_relationships_errors(
-            errors, self._validate_all_tables_connected, parent_map, child_map)
-
         if errors:
             raise InvalidMetadataError(
                 'The metadata is not valid' + '\n'.join(str(e) for e in errors)

tests/unit/metadata/test_multi_table.py

@@ -1195,21 +1195,16 @@ def test_validate_raises_errors(self):
 
         # Run
         error_msg = re.escape(
-            'The metadata is not valid\n'
-            '\nTable: payments'
-            "\nInvalid regex format string '[A-z{' for id column 'date'."
-            '\n\nRelationships:'
-            "\nThe parent table 'users' does not have a primary key set. "
-            "Please use 'set_primary_key' in order to set one."
-            "\nRelationship between tables ('sessions', 'transactions') is invalid. "
-            'The primary and foreign key columns are not the same type.'
-            "\nThe relationships in the dataset are disjointed. Table ['payments'] "
-            'is not connected to any of the other tables.'
+            'The relationships in the dataset are disjointed. '
+            "Table ['payments'] is not connected to any of the other tables."
         )
 
         # Run and Assert
         with pytest.raises(InvalidMetadataError, match=error_msg):
-            instance.validate()
+            instance._validate_all_tables_connected(
+                instance._get_parent_map(),
+                instance._get_child_map()
+            )
 
     def test_validate_child_key_is_primary_key(self):
         """Test it crashes if the child key is a primary key."""
@@ -2324,44 +2319,6 @@ def test__detect_relationships(self):
         assert instance.relationships == expected_relationships
         assert instance.tables['sessions'].columns['user_id']['sdtype'] == 'id'
 
-    @patch('sdv.metadata.multi_table.warnings')
-    def test__detect_relationships_disconnected_warning(self, warnings_mock):
-        """Test that ``_detect_relationships`` warns about tables it could not connect."""
-        # Setup
-        parent_table = Mock()
-        parent_table.primary_key = 'id'
-        parent_table.columns = {
-            'id': {'sdtype': 'id'},
-            'user_name': {'sdtype': 'categorical'},
-            'transactions': {'sdtype': 'numerical'},
-        }
-
-        child_table = SingleTableMetadata()
-        child_table.primary_key = 'session_id'
-        child_table.columns = {
-            'user_id': {'sdtype': 'categorical'},
-            'session_id': {'sdtype': 'numerical'},
-            'timestamp': {'sdtype': 'datetime'},
-        }
-
-        instance = MultiTableMetadata()
-        instance.tables = {
-            'users': parent_table,
-            'sessions': child_table,
-        }
-
-        # Run
-        instance._detect_relationships()
-
-        # Assert
-        expected_warning = (
-            'Could not automatically add relationships for all tables. The relationships in '
-            "the dataset are disjointed. Tables ['users', 'sessions'] are not connected to "
-            'any of the other tables.'
-        )
-        warnings_mock.warn.assert_called_once_with(expected_warning)
-        assert instance.relationships == []
-
     def test__detect_relationships_circular(self):
         """Test that relationships that invalidate the metadata are not added."""
         # Setup