chore: Adding schema name property in dbapi connection (#1101)

* chore: Adding schema name property in dbapi connection

* small fix

* More changes

* 🦉 Updates from OwlBot post-processor

See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md

* Comments incorporated

* 🦉 Updates from OwlBot post-processor

See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md

* Comments incorporated

* lint issues fixed

* comment incorporated

---------

Co-authored-by: Owl Bot <gcf-owl-bot[bot]@users.noreply.github.com>

Author: ankiaga

google/cloud/spanner_dbapi/connection.py

@@ -124,6 +124,18 @@ def spanner_client(self):
         """
         return self._instance._client
 
+    @property
+    def current_schema(self):
+        """schema name for this connection.
+
+        :rtype: str
+        :returns: the current default schema of this connection. Currently, this
+         is always "" for GoogleSQL and "public" for PostgreSQL databases.
+        """
+        if self.database is None:
+            raise ValueError("database property not set on the connection")
+        return self.database.default_schema_name
+
     @property
     def autocommit(self):
         """Autocommit mode flag for this connection.
@@ -664,9 +676,10 @@ def connect(
             raise ValueError("project in url does not match client object project")
 
     instance = client.instance(instance_id)
-    conn = Connection(
-        instance, instance.database(database_id, pool=pool) if database_id else None
-    )
+    database = None
+    if database_id:
+        database = instance.database(database_id, pool=pool)
+    conn = Connection(instance, database)
     if pool is not None:
         conn._own_pool = False
 

tests/unit/spanner_dbapi/test_connection.py

@@ -20,6 +20,7 @@
 import warnings
 import pytest
 
+from google.cloud.spanner_admin_database_v1 import DatabaseDialect
 from google.cloud.spanner_dbapi.batch_dml_executor import BatchMode
 from google.cloud.spanner_dbapi.exceptions import (
     InterfaceError,
@@ -58,14 +59,16 @@ def _get_client_info(self):
 
         return ClientInfo(user_agent=USER_AGENT)
 
-    def _make_connection(self, **kwargs):
+    def _make_connection(
+        self, database_dialect=DatabaseDialect.DATABASE_DIALECT_UNSPECIFIED, **kwargs
+    ):
         from google.cloud.spanner_v1.instance import Instance
         from google.cloud.spanner_v1.client import Client
 
         # We don't need a real Client object to test the constructor
         client = Client()
         instance = Instance(INSTANCE, client=client)
-        database = instance.database(DATABASE)
+        database = instance.database(DATABASE, database_dialect=database_dialect)
         return Connection(instance, database, **kwargs)
 
     @mock.patch("google.cloud.spanner_dbapi.connection.Connection.commit")
@@ -105,6 +108,22 @@ def test_property_instance(self):
         self.assertIsInstance(connection.instance, Instance)
         self.assertEqual(connection.instance, connection._instance)
 
+    def test_property_current_schema_google_sql_dialect(self):
+        from google.cloud.spanner_v1.database import Database
+
+        connection = self._make_connection(
+            database_dialect=DatabaseDialect.GOOGLE_STANDARD_SQL
+        )
+        self.assertIsInstance(connection.database, Database)
+        self.assertEqual(connection.current_schema, "")
+
+    def test_property_current_schema_postgres_sql_dialect(self):
+        from google.cloud.spanner_v1.database import Database
+
+        connection = self._make_connection(database_dialect=DatabaseDialect.POSTGRESQL)
+        self.assertIsInstance(connection.database, Database)
+        self.assertEqual(connection.current_schema, "public")
+
     def test_read_only_connection(self):
         connection = self._make_connection(read_only=True)
         self.assertTrue(connection.read_only)
@@ -745,11 +764,22 @@ def __init__(self, name="instance_id", client=None):
         self.name = name
         self._client = client
 
-    def database(self, database_id="database_id", pool=None):
-        return _Database(database_id, pool)
+    def database(
+        self,
+        database_id="database_id",
+        pool=None,
+        database_dialect=DatabaseDialect.GOOGLE_STANDARD_SQL,
+    ):
+        return _Database(database_id, pool, database_dialect)
 
 
 class _Database(object):
-    def __init__(self, database_id="database_id", pool=None):
+    def __init__(
+        self,
+        database_id="database_id",
+        pool=None,
+        database_dialect=DatabaseDialect.GOOGLE_STANDARD_SQL,
+    ):
         self.name = database_id
         self.pool = pool
+        self.database_dialect = database_dialect