changed autofield and bigautofield to use integer, added default value generators, updated integration tests , added disable server side cursor

Author: Victor Tsang

aurora_dsql_django/base.py

@@ -29,6 +29,34 @@
 from .operations import DatabaseOperations
 from .schema import DatabaseSchemaEditor
 
+from uuid import uuid4
+
+from django.db.models.fields import (
+    AutoField,
+    BigAutoField,
+    Field,
+)
+
+def uuid_to_int32():
+    return uuid4().int & 0x7FFFFFFF
+
+def uuid_to_int64():
+    return uuid4().int & 0x7FFFFFFFFFFFFFFF
+
+def patch_autofield(field_class, generator):
+    def __init__(self, *args, **kwargs):
+        kwargs["blank"] = True
+        Field.__init__(self, *args, **kwargs)
+        self.default = generator
+    
+    field_class.__init__ = __init__
+    field_class.validators = []
+    field_class.db_returning = False
+
+# patch AutoFields to get default value from generator functions
+patch_autofield(AutoField, uuid_to_int32) 
+patch_autofield(BigAutoField, uuid_to_int64)
+
 logger = logging.getLogger(__name__)
 
 
@@ -93,16 +121,14 @@ class DatabaseWrapper(base.DatabaseWrapper):
     # Override some types from the postgresql adapter.
     data_types = dict(
         base.DatabaseWrapper.data_types,
-        BigAutoField="uuid",
-        AutoField="uuid",
         DateTimeField="timestamptz",
     )
     data_types_suffix = dict(
         base.DatabaseWrapper.data_types_suffix,
-        BigAutoField="DEFAULT gen_random_uuid()",
+        BigAutoField="", # Default value auto generated from gen_rand_int64
         # For now skipping small int because uuid does not fit in a smallint?
         SmallAutoField="",
-        AutoField="DEFAULT gen_random_uuid()",
+        AutoField="", # Default value auto generated from gen_rand_int32
     )
 
     SchemaEditorClass = DatabaseSchemaEditor

aurora_dsql_django/operations.py

@@ -22,12 +22,6 @@
 
 class DatabaseOperations(operations.DatabaseOperations):
 
-    cast_data_types = {
-        "AutoField": "uuid",
-        "BigAutoField": "uuid",
-        "SmallAutoField": "smallint",
-    }
-
     def deferrable_sql(self):
         # Deferrable constraints aren't supported:
         return ""

aurora_dsql_django/schema.py

@@ -25,10 +25,11 @@ class DatabaseSchemaEditor(schema.DatabaseSchemaEditor):
     # The PostgreSQL backend uses "SET CONSTRAINTS ... IMMEDIATE" before
     # "ALTER TABLE..." to run any any deferred checks to allow dropping the
     # foreign key in the same transaction. This doesn't apply to Aurora DSQL.
-    sql_delete_fk = ""
+    # A zero row count no-op valid SQL query with source name (useful for debugging)
+    sql_delete_fk = "SELECT 'sql_delete_fk' WHERE FALSE" 
 
     # ALTER TABLE ADD CONSTRAINT PRIMARY KEY is not supported
-    sql_create_pk = ""
+    sql_create_pk = "SELECT 'sql_create_pk' WHERE FALSE"
 
     # "ALTER TABLE ... DROP CONSTRAINT ..." not supported for dropping UNIQUE
     # constraints; must use this instead.
@@ -40,18 +41,25 @@ class DatabaseSchemaEditor(schema.DatabaseSchemaEditor):
         "UPDATE %(table)s SET %(column)s = %(default)s WHERE %(column)s IS NULL"
     )
 
-    # ALTER TABLE ADD CONSTRAINT is not supported
-    sql_create_unique = ""
+    # ALTER TABLE ADD CONSTRAINT is not supported, but create unique index async works as an alternative 
+    sql_create_unique = "CREATE UNIQUE INDEX ASYNC %(name)s ON %(table)s (%(columns)s)"
 
     # ALTER TABLE ADD CONSTRAINT FOREIGN KEY is not supported
-    sql_create_fk = ""
+    sql_create_fk = "SELECT 'sql_create_fk' WHERE FALSE"
     # ALTER TABLE ADD CONSTRAINT CHECK is not supported
-    sql_create_check = ""
-    sql_delete_check = ""
+    sql_create_check = "SELECT 'sql_create_check' WHERE FALSE"
+    sql_delete_check = "SELECT 'sql_delete_check' WHERE FALSE"
     # ALTER TABLE DROP CONSTRAINT is not supported
-    sql_delete_constraint = ""
+    sql_delete_constraint = "SELECT 'sql_delete_constraint' WHERE FALSE"
     # ALTER TABLE DROP COLUMN is not supported
-    sql_delete_column = ""
+    sql_delete_column = "SELECT 'sql_delete_column' WHERE FALSE"
+
+    sql_create_index = (
+        "CREATE INDEX ASYNC %(name)s ON %(table)s%(using)s "
+        "(%(columns)s)%(include)s%(extra)s%(condition)s"
+    )
+
+    sql_alter_column = "SELECT 'sql_alter_column' WHERE FALSE"
 
     def __enter__(self):
         super().__enter__()

aurora_dsql_django/tests/unit/test_base.py

@@ -106,19 +106,17 @@ def test_get_aws_connection_params_error_handling(self, mock_session):
 
     def test_database_wrapper_data_types(self):
         wrapper = DatabaseWrapper({})
-        self.assertEqual(wrapper.data_types['BigAutoField'], "uuid")
-        self.assertEqual(wrapper.data_types['AutoField'], "uuid")
         self.assertEqual(wrapper.data_types['DateTimeField'], "timestamptz")
 
     def test_database_wrapper_data_types_suffix(self):
         wrapper = DatabaseWrapper({})
         self.assertEqual(
             wrapper.data_types_suffix['BigAutoField'],
-            "DEFAULT gen_random_uuid()")
+            "")
         self.assertEqual(wrapper.data_types_suffix['SmallAutoField'], "")
         self.assertEqual(
             wrapper.data_types_suffix['AutoField'],
-            "DEFAULT gen_random_uuid()")
+            "")
 
     @patch('aurora_dsql_django.base.get_aws_connection_params')
     def test_database_wrapper_get_connection_params(self, mock_get_aws_params):

aurora_dsql_django/tests/unit/test_operations.py

@@ -11,8 +11,8 @@ def setUp(self):
 
     def test_cast_data_types(self):
         expected_cast_data_types = {
-            "AutoField": "uuid",
-            "BigAutoField": "uuid",
+            "AutoField": "integer",
+            "BigAutoField": "bigint",
             "SmallAutoField": "smallint",
         }
         self.assertEqual(self.ops.cast_data_types, expected_cast_data_types)
@@ -29,21 +29,6 @@ def test_inheritance(self):
         from django.db.backends.postgresql.operations import DatabaseOperations as PostgreSQLDatabaseOperations
         self.assertIsInstance(self.ops, PostgreSQLDatabaseOperations)
 
-    def test_overridden_attributes(self):
-        from django.db.backends.postgresql.operations import DatabaseOperations as PostgreSQLDatabaseOperations
-        postgresql_ops = PostgreSQLDatabaseOperations(None)
-
-        # Check that we've actually overridden some attributes
-        self.assertNotEqual(
-            self.ops.cast_data_types,
-            postgresql_ops.cast_data_types)
-
-    def test_cast_data_types_autofield(self):
-        self.assertEqual(self.ops.cast_data_types['AutoField'], 'uuid')
-
-    def test_cast_data_types_bigautofield(self):
-        self.assertEqual(self.ops.cast_data_types['BigAutoField'], 'uuid')
-
     def test_cast_data_types_smallautofield(self):
         self.assertEqual(
             self.ops.cast_data_types['SmallAutoField'],

aurora_dsql_django/tests/unit/test_schema.py

@@ -11,21 +11,21 @@ def setUp(self):
         self.schema_editor = DatabaseSchemaEditor(self.connection)
 
     def test_sql_attributes(self):
-        self.assertEqual(self.schema_editor.sql_delete_fk, "")
-        self.assertEqual(self.schema_editor.sql_create_pk, "")
+        self.assertEqual(self.schema_editor.sql_delete_fk, "SELECT 'sql_delete_fk' WHERE FALSE")
+        self.assertEqual(self.schema_editor.sql_create_pk, "SELECT 'sql_create_pk' WHERE FALSE")
         self.assertEqual(
             self.schema_editor.sql_delete_unique,
             "DROP INDEX %(name)s CASCADE")
         self.assertEqual(
             self.schema_editor.sql_update_with_default,
             "UPDATE %(table)s SET %(column)s = %(default)s WHERE %(column)s IS NULL"
         )
-        self.assertEqual(self.schema_editor.sql_create_unique, "")
-        self.assertEqual(self.schema_editor.sql_create_fk, "")
-        self.assertEqual(self.schema_editor.sql_create_check, "")
-        self.assertEqual(self.schema_editor.sql_delete_check, "")
-        self.assertEqual(self.schema_editor.sql_delete_constraint, "")
-        self.assertEqual(self.schema_editor.sql_delete_column, "")
+        self.assertEqual(self.schema_editor.sql_create_unique, "SELECT 'sql_create_unique' WHERE FALSE")
+        self.assertEqual(self.schema_editor.sql_create_fk, "SELECT 'sql_create_fk' WHERE FALSE")
+        self.assertEqual(self.schema_editor.sql_create_check, "SELECT 'sql_create_check' WHERE FALSE")
+        self.assertEqual(self.schema_editor.sql_delete_check, "SELECT 'sql_delete_check' WHERE FALSE")
+        self.assertEqual(self.schema_editor.sql_delete_constraint, "SELECT 'sql_delete_constraint' WHERE FALSE")
+        self.assertEqual(self.schema_editor.sql_delete_column, "SELECT 'sql_delete_column' WHERE FALSE")
 
     @patch('aurora_dsql_django.schema.schema.DatabaseSchemaEditor.add_index')
     def test_add_index_with_expressions(self, mock_super_add_index):

examples/pet-clinic-app/project/project/settings.py

@@ -71,6 +71,7 @@
         'USER': 'admin',
         'NAME': 'postgres',
         'ENGINE': 'aurora_dsql_django',
+        'DISABLE_SERVER_SIDE_CURSORS': True,
         'OPTIONS': {
             'sslmode': 'require',
             'region': 'us-east-1'