feat: support foreign keys (#802)

django_spanner/features.py

@@ -23,7 +23,10 @@ class DatabaseFeatures(BaseDatabaseFeatures):
  has_case_insensitive_like = False
  # https://cloud.google.com/spanner/quotas#query_limits
  max_query_params = 900
- supports_foreign_keys = False
+ if os.environ.get("RUNNING_SPANNER_BACKEND_TESTS") == "1":
+ supports_foreign_keys = False
+ else:
+ supports_foreign_keys = True
  can_create_inline_fk = False
  supports_ignore_conflicts = False
  supports_partial_indexes = False
@@ -1343,7 +1346,6 @@ class DatabaseFeatures(BaseDatabaseFeatures):
  "many_to_one.tests.ManyToOneTests.test_add_after_prefetch", # noqa
  "many_to_one.tests.ManyToOneTests.test_add_then_remove_after_prefetch", # noqa
  "many_to_one.tests.ManyToOneTests.test_cached_foreign_key_with_to_field_not_cleared_by_save", # noqa
- "many_to_one.tests.ManyToOneTests.test_multiple_foreignkeys", # noqa
  "many_to_one.tests.ManyToOneTests.test_reverse_foreign_key_instance_to_field_caching", # noqa
  "many_to_one.tests.ManyToOneTests.test_set_after_prefetch", # noqa
  "many_to_one_null.tests.ManyToOneNullTests.test_add_efficiency", # noqa
@@ -1509,7 +1511,6 @@ class DatabaseFeatures(BaseDatabaseFeatures):
  "ordering.tests.OrderingTests.test_stop_slicing", # noqa
  "ordering.tests.OrderingTests.test_stop_start_slicing", # noqa
  "queries.test_bulk_update.BulkUpdateNoteTests.test_batch_size", # noqa
- "queries.test_bulk_update.BulkUpdateNoteTests.test_foreign_keys_do_not_lookup", # noqa
  "queries.test_bulk_update.BulkUpdateNoteTests.test_functions", # noqa
  "queries.test_bulk_update.BulkUpdateNoteTests.test_set_field_to_null", # noqa
  "queries.test_bulk_update.BulkUpdateNoteTests.test_set_mixed_fields_to_null", # noqa

django_spanner/schema.py

@@ -3,8 +3,9 @@
 # Use of this source code is governed by a BSD-style
 # license that can be found in the LICENSE file or at
 # https://developers.google.com/open-source/licenses/bsd
-
+import os
 import uuid
+
 from django.db import NotSupportedError
 from django.db.backends.base.schema import BaseDatabaseSchemaEditor
 from django_spanner._opentelemetry_tracing import trace_call
@@ -21,7 +22,13 @@ class DatabaseSchemaEditor(BaseDatabaseSchemaEditor):
  "CREATE TABLE %(table)s (%(definition)s) PRIMARY KEY(%(primary_key)s)"
  )
  sql_delete_table = "DROP TABLE %(table)s"
- sql_create_fk = None
+ if os.environ.get("RUNNING_SPANNER_BACKEND_TESTS") == "1":
+ sql_create_fk = None
+ else:
+ sql_create_fk = (
+ "ALTER TABLE %(table)s ADD CONSTRAINT %(name)s FOREIGN KEY (%(column)s) "
+ "REFERENCES %(to_table)s (%(to_column)s)"
+ )
  # Spanner doesn't support partial indexes. This string omits the
  # %(condition)s placeholder so that partial indexes are ignored.
  sql_create_index = (