Remove input error on null foreign keys from BaseMultiTableSynthesize…

…r.fit (#2077)

sdv/multi_table/base.py

@@ -14,7 +14,6 @@
 
 from sdv import version
 from sdv._utils import (
-    _validate_foreign_keys_not_null,
     check_sdv_versions_and_warn,
     check_synthesizer_version,
     generate_synthesizer_id,
@@ -457,7 +456,6 @@ def fit(self, data):
         })
 
         check_synthesizer_version(self, is_fit_method=True, compare_operator=operator.lt)
-        _validate_foreign_keys_not_null(self.metadata, data)
         self._check_metadata_updated()
         self._fitted = False
         processed_data = self.preprocess(data)

tests/integration/multi_table/test_hma.py

@@ -1316,7 +1316,7 @@ def test_metadata_updated_warning_detect(self):
         assert len(record) == 1
 
     def test_null_foreign_keys(self):
-        """Test that the synthesizer crashes when there are null foreign keys."""
+        """Test that the synthesizer does not crash when there are null foreign keys."""
         # Setup
         metadata = MultiTableMetadata()
         metadata.add_table('parent_table')
@@ -1372,16 +1372,7 @@ def test_null_foreign_keys(self):
         metadata.validate_data(data)
 
         # Run and Assert
-        err_msg = re.escape(
-            'The data contains null values in foreign key columns. This feature is currently '
-            'unsupported. Please remove null values to fit the synthesizer.\n'
-            '\n'
-            'Affected columns:\n'
-            "Table 'child_table1', column(s) ['fk']\n"
-            "Table 'child_table2', column(s) ['fk1', 'fk2']\n"
-        )
-        with pytest.raises(SynthesizerInputError, match=err_msg):
-            synthesizer.fit(data)
+        synthesizer.fit(data)
 
     def test_sampling_with_unknown_sdtype_numerical_column(self):
         """Test that if a numerical column is detected as unknown in the metadata,

tests/unit/multi_table/test_base.py

@@ -1067,8 +1067,7 @@ def test_fit_processed_data_raises_version_error(self):
         instance._check_metadata_updated.assert_not_called()
 
     @patch('sdv.multi_table.base.datetime')
-    @patch('sdv.multi_table.base._validate_foreign_keys_not_null')
-    def test_fit(self, mock_validate_foreign_keys_not_null, mock_datetime, caplog):
+    def test_fit(self, mock_datetime, caplog):
         """Test that it calls the appropriate methods."""
         # Setup
         mock_datetime.datetime.now.return_value = '2024-04-19 16:20:10.037183'
@@ -1088,7 +1087,6 @@ def test_fit(self, mock_validate_foreign_keys_not_null, mock_datetime, caplog):
             BaseMultiTableSynthesizer.fit(instance, data)
 
         # Assert
-        mock_validate_foreign_keys_not_null.assert_called_once_with(instance.metadata, data)
         instance.preprocess.assert_called_once_with(data)
         instance.fit_processed_data.assert_called_once_with(instance.preprocess.return_value)
         instance._check_metadata_updated.assert_called_once()