feat: foreign key on delete cascade action testing and samples (#910)

* feat: fkdca

* lint

* lint

* Update samples/samples/snippets.py

Co-authored-by: Vishwaraj Anand <vishwaraj.anand00@gmail.com>

* Update samples/samples/snippets.py

Co-authored-by: Vishwaraj Anand <vishwaraj.anand00@gmail.com>

* changed

* changes

---------

Co-authored-by: Vishwaraj Anand <vishwaraj.anand00@gmail.com>

samples/samples/snippets.py

@@ -2449,6 +2449,105 @@ def enable_fine_grained_access(
     # [END spanner_enable_fine_grained_access]
 
 
+# [START spanner_create_table_with_foreign_key_delete_cascade]
+def create_table_with_foreign_key_delete_cascade(instance_id, database_id):
+    """Creates a table with foreign key delete cascade action"""
+    spanner_client = spanner.Client()
+    instance = spanner_client.instance(instance_id)
+    database = instance.database(database_id)
+
+    operation = database.update_ddl(
+        [
+            """CREATE TABLE Customers (
+               CustomerId INT64 NOT NULL,
+               CustomerName STRING(62) NOT NULL,
+               ) PRIMARY KEY (CustomerId)
+            """,
+            """
+               CREATE TABLE ShoppingCarts (
+               CartId INT64 NOT NULL,
+               CustomerId INT64 NOT NULL,
+               CustomerName STRING(62) NOT NULL,
+               CONSTRAINT FKShoppingCartsCustomerId FOREIGN KEY (CustomerId)
+               REFERENCES Customers (CustomerId) ON DELETE CASCADE
+               ) PRIMARY KEY (CartId)
+            """
+        ]
+    )
+
+    print("Waiting for operation to complete...")
+    operation.result(OPERATION_TIMEOUT_SECONDS)
+
+    print(
+        """Created Customers and ShoppingCarts table with FKShoppingCartsCustomerId
+           foreign key constraint on database {} on instance {}""".format(
+           database_id, instance_id
+        )
+    )
+
+
+# [END spanner_create_table_with_foreign_key_delete_cascade]
+
+
+# [START spanner_alter_table_with_foreign_key_delete_cascade]
+def alter_table_with_foreign_key_delete_cascade(instance_id, database_id):
+    """Alters a table with foreign key delete cascade action"""
+    spanner_client = spanner.Client()
+    instance = spanner_client.instance(instance_id)
+    database = instance.database(database_id)
+
+    operation = database.update_ddl(
+        [
+            """ALTER TABLE ShoppingCarts
+               ADD CONSTRAINT FKShoppingCartsCustomerName
+               FOREIGN KEY (CustomerName)
+               REFERENCES Customers(CustomerName)
+               ON DELETE CASCADE"""
+        ]
+    )
+
+    print("Waiting for operation to complete...")
+    operation.result(OPERATION_TIMEOUT_SECONDS)
+
+    print(
+        """Altered ShoppingCarts table with FKShoppingCartsCustomerName
+           foreign key constraint on database {} on instance {}""".format(
+           database_id, instance_id
+        )
+    )
+
+
+# [END spanner_alter_table_with_foreign_key_delete_cascade]
+
+
+# [START spanner_drop_foreign_key_constraint_delete_cascade]
+def drop_foreign_key_constraint_delete_cascade(instance_id, database_id):
+    """Alter table to drop foreign key delete cascade action"""
+    spanner_client = spanner.Client()
+    instance = spanner_client.instance(instance_id)
+    database = instance.database(database_id)
+
+    operation = database.update_ddl(
+        [
+            """ALTER TABLE ShoppingCarts
+               DROP CONSTRAINT FKShoppingCartsCustomerName"""
+        ]
+    )
+
+    print("Waiting for operation to complete...")
+    operation.result(OPERATION_TIMEOUT_SECONDS)
+
+    print(
+        """Altered ShoppingCarts table to drop FKShoppingCartsCustomerName
+           foreign key constraint on database {} on instance {}""".format(
+           database_id, instance_id
+        )
+    )
+
+
+# [END spanner_drop_foreign_key_constraint_delete_cascade]
+
+
 if __name__ == "__main__":  # noqa: C901
     parser = argparse.ArgumentParser(
         description=__doc__, formatter_class=argparse.RawDescriptionHelpFormatter

samples/samples/snippets_test.py

@@ -794,3 +794,25 @@ def test_list_database_roles(capsys, instance_id, sample_database):
     snippets.list_database_roles(instance_id, sample_database.database_id)
     out, _ = capsys.readouterr()
     assert "new_parent" in out
+
+
+@pytest.mark.dependency(name="create_table_with_foreign_key_delete_cascade")
+def test_create_table_with_foreign_key_delete_cascade(capsys, instance_id, sample_database):
+    snippets.create_table_with_foreign_key_delete_cascade(instance_id, sample_database.database_id)
+    out, _ = capsys.readouterr()
+    assert "Created Customers and ShoppingCarts table with FKShoppingCartsCustomerId" in out
+
+
+@pytest.mark.dependency(name="alter_table_with_foreign_key_delete_cascade",
+                        depends=["create_table_with_foreign_key_delete_cascade"])
+def test_alter_table_with_foreign_key_delete_cascade(capsys, instance_id, sample_database):
+    snippets.alter_table_with_foreign_key_delete_cascade(instance_id, sample_database.database_id)
+    out, _ = capsys.readouterr()
+    assert "Altered ShoppingCarts table with FKShoppingCartsCustomerName" in out
+
+
+@pytest.mark.dependency(depends=["alter_table_with_foreign_key_delete_cascade"])
+def test_drop_foreign_key_contraint_delete_cascade(capsys, instance_id, sample_database):
+    snippets.drop_foreign_key_constraint_delete_cascade(instance_id, sample_database.database_id)
+    out, _ = capsys.readouterr()
+    assert "Altered ShoppingCarts table to drop FKShoppingCartsCustomerName" in out

tests/_fixtures.py

@@ -68,6 +68,19 @@
      email STRING(MAX),
      deleted BOOL NOT NULL )
      PRIMARY KEY(id, commit_ts DESC);
+
+CREATE TABLE Customers (
+    CustomerId INT64 NOT NULL,
+    CustomerName STRING(62) NOT NULL,
+    ) PRIMARY KEY (CustomerId);
+
+    CREATE TABLE ShoppingCarts (
+    CartId INT64 NOT NULL,
+    CustomerId INT64 NOT NULL,
+    CustomerName STRING(62) NOT NULL,
+    CONSTRAINT FKShoppingCartsCustomerId FOREIGN KEY (CustomerId)
+    REFERENCES Customers (CustomerId) ON DELETE CASCADE
+    ) PRIMARY KEY (CartId);
 """
 
 EMULATOR_DDL = """\
@@ -157,6 +170,19 @@
     name VARCHAR(16),
     PRIMARY KEY (id));
 CREATE INDEX name ON contacts(first_name, last_name);
+CREATE TABLE Customers (
+    CustomerId BIGINT,
+    CustomerName VARCHAR(62) NOT NULL,
+    PRIMARY KEY (CustomerId));
+
+    CREATE TABLE ShoppingCarts (
+    CartId BIGINT,
+    CustomerId BIGINT NOT NULL,
+    CustomerName VARCHAR(62) NOT NULL,
+    CONSTRAINT "FKShoppingCartsCustomerId" FOREIGN KEY (CustomerId)
+    REFERENCES Customers (CustomerId) ON DELETE CASCADE,
+    PRIMARY KEY (CartId)
+    );
 """
 
 DDL_STATEMENTS = [stmt.strip() for stmt in DDL.split(";") if stmt.strip()]

tests/system/test_database_api.py

@@ -21,13 +21,16 @@
 from google.iam.v1 import policy_pb2
 from google.cloud import spanner_v1
 from google.cloud.spanner_v1.pool import FixedSizePool, PingingPool
+from google.cloud.spanner_admin_database_v1 import DatabaseDialect
 from google.type import expr_pb2
 from . import _helpers
 from . import _sample_data
-from google.cloud.spanner_admin_database_v1 import DatabaseDialect
 
 
 DBAPI_OPERATION_TIMEOUT = 240  # seconds
+FKADC_CUSTOMERS_COLUMNS = ("CustomerId", "CustomerName")
+FKADC_SHOPPING_CARTS_COLUMNS = ("CartId", "CustomerId", "CustomerName")
+ALL_KEYSET = spanner_v1.KeySet(all_=True)
 
 
 @pytest.fixture(scope="module")
@@ -572,6 +575,135 @@ def _unit_of_work(transaction, name):
     assert len(rows) == 2
 
 
+def test_insertion_in_referencing_table_fkadc(not_emulator, shared_database):
+    with shared_database.batch() as batch:
+        batch.insert(
+            table="Customers",
+            columns=FKADC_CUSTOMERS_COLUMNS,
+            values=[
+                (1, "Marc"),
+                (2, "Catalina"),
+            ],
+        )
+
+    with shared_database.batch() as batch:
+        batch.insert(
+            table="ShoppingCarts",
+            columns=FKADC_SHOPPING_CARTS_COLUMNS,
+            values=[
+                (1, 1, "Marc"),
+            ],
+        )
+
+    with shared_database.snapshot() as snapshot:
+        rows = list(
+            snapshot.read(
+                "ShoppingCarts", ("CartId", "CustomerId", "CustomerName"), ALL_KEYSET
+            )
+        )
+
+    assert len(rows) == 1
+
+
+def test_insertion_in_referencing_table_error_fkadc(not_emulator, shared_database):
+    with pytest.raises(exceptions.FailedPrecondition):
+        with shared_database.batch() as batch:
+            batch.insert(
+                table="ShoppingCarts",
+                columns=FKADC_SHOPPING_CARTS_COLUMNS,
+                values=[
+                    (4, 4, "Naina"),
+                ],
+            )
+
+
+def test_insertion_then_deletion_in_referenced_table_fkadc(
+    not_emulator, shared_database
+):
+    with shared_database.batch() as batch:
+        batch.insert(
+            table="Customers",
+            columns=FKADC_CUSTOMERS_COLUMNS,
+            values=[
+                (3, "Sara"),
+            ],
+        )
+
+    with shared_database.batch() as batch:
+        batch.insert(
+            table="ShoppingCarts",
+            columns=FKADC_SHOPPING_CARTS_COLUMNS,
+            values=[
+                (3, 3, "Sara"),
+            ],
+        )
+
+    with shared_database.snapshot() as snapshot:
+        rows = list(snapshot.read("ShoppingCarts", ["CartId"], ALL_KEYSET))
+
+    assert [3] in rows
+
+    with shared_database.batch() as batch:
+        batch.delete(table="Customers", keyset=spanner_v1.KeySet(keys=[[3]]))
+
+    with shared_database.snapshot() as snapshot:
+        rows = list(snapshot.read("ShoppingCarts", ["CartId"], ALL_KEYSET))
+
+    assert [3] not in rows
+
+
+def test_insert_then_delete_referenced_key_error_fkadc(not_emulator, shared_database):
+    with pytest.raises(exceptions.FailedPrecondition):
+        with shared_database.batch() as batch:
+            batch.insert(
+                table="Customers",
+                columns=FKADC_CUSTOMERS_COLUMNS,
+                values=[
+                    (3, "Sara"),
+                ],
+            )
+            batch.delete(table="Customers", keyset=spanner_v1.KeySet(keys=[[3]]))
+
+
+def test_insert_referencing_key_then_delete_referenced_key_error_fkadc(
+    not_emulator, shared_database
+):
+    with shared_database.batch() as batch:
+        batch.insert(
+            table="Customers",
+            columns=FKADC_CUSTOMERS_COLUMNS,
+            values=[
+                (4, "Huda"),
+            ],
+        )
+
+    with pytest.raises(exceptions.FailedPrecondition):
+        with shared_database.batch() as batch:
+            batch.insert(
+                table="ShoppingCarts",
+                columns=FKADC_SHOPPING_CARTS_COLUMNS,
+                values=[
+                    (4, 4, "Huda"),
+                ],
+            )
+            batch.delete(table="Customers", keyset=spanner_v1.KeySet(keys=[[4]]))
+
+
+def test_information_schema_referential_constraints_fkadc(
+    not_emulator, shared_database
+):
+    with shared_database.snapshot() as snapshot:
+        rows = list(
+            snapshot.execute_sql(
+                "SELECT DELETE_RULE "
+                "FROM INFORMATION_SCHEMA.REFERENTIAL_CONSTRAINTS "
+                "WHERE CONSTRAINT_NAME = 'FKShoppingCartsCustomerId'"
+            )
+        )
+
+        assert any("CASCADE" in stmt for stmt in rows)
+
+
 def test_update_database_success(
     not_emulator, shared_database, shared_instance, database_operation_timeout
 ):