Use oracledb default setting instead of output type handler

gobcore/datastore/oracle.py

@@ -1,6 +1,6 @@
 from pathlib import Path
 from collections.abc import Iterator, Callable
-from typing import Optional, Any
+from typing import Any
 
 import os
 import oracledb
@@ -28,6 +28,10 @@
 """
 os.environ["NLS_LANG"] = ".UTF8"
 
+# returns strings or bytes instead of a locator
+# https://python-oracledb.readthedocs.io/en/latest/user_guide/lob_data.html#fetching-lobs-as-strings-and-bytes
+oracledb.defaults.fetch_lobs = False
+
 
 class OracleDatastore(SqlDatastore):
 
@@ -73,15 +77,12 @@ def connect(self) -> oracledb.Connection:
         dsn = self._build_connection_string(**self.connection_config, params=dict(params))
 
         try:
-            connection = oracledb.connect(dsn)
+            self.connection = oracledb.connect(dsn)
         except oracledb.OperationalError as e:
             raise GOBException(
                 f"Database connection for source {self.connection_config['name']} {self.user} failed: {e}"
             )
-
-        connection.outputtypehandler = self._output_type_handler
-        self.connection = connection
-        return connection
+        return self.connection
 
     def query(self, query: str, **kwargs) -> Iterator[dict[str, Any]]:
         """Return query result iterator from the database formatted as dictionary."""
@@ -100,7 +101,7 @@ def execute(self, query: str) -> None:
         """Executes a SQL statement on the database and commits the changes."""
         with self.connection.cursor() as cur:
             cur.execute(query)
-            self.connection.commit()
+        self.connection.commit()
 
     def list_tables_for_schema(self, schema: str) -> list[str]:
         raise NotImplementedError("Please implement list_tables_for_schema for OracleDatastore")
@@ -125,10 +126,3 @@ def _dict_cursor(cursor: oracledb.Cursor) -> Callable[..., dict[str, Any]]:
         """Convert query tuple a dictionary with column names as keys."""
         cols = [d[0].lower() for d in cursor.description]
         return lambda *args: dict(zip(cols, args))
-
-    @staticmethod
-    def _output_type_handler(
-            cursor: oracledb.Cursor, name: str, default_type, size, precision, scale
-    ) -> Optional[oracledb.Var]:
-        if default_type == oracledb.CLOB:
-            return cursor.var(oracledb.LONG_STRING, arraysize=cursor.arraysize)

tests/gobcore/datastore/test_oracle.py

@@ -38,6 +38,8 @@ def test_init(self, mock_temp, mock_path, mock_init_client):
         OracleDatastore(self.config)
         mock_init_client.assert_not_called()
 
+        assert oracledb.defaults.fetch_lobs is False
+
     def test_init_missing_keys(self):
         with self.assertRaisesRegex(GOBException, "database,password,port,username"):
             OracleDatastore({"name": "my config", "host": "my_host"})
@@ -50,7 +52,6 @@ def test_connect(self, mock_connect):
             "username/password@tcp://host1:1234,host2:1234/SID?"
             "retry_count=3&connection_timeout=3&failover=on&load_balance=off"
         )
-        assert self.store.connection.outputtypehandler == self.store._output_type_handler
         assert self.store.connection == conn == mock_connect.return_value
 
         # single host
@@ -69,15 +70,6 @@ def test_connect_opserror(self, _):
     def test_makedict(self, mock_cursor):
         assert {"a": 1, "b": 2, "c": 3} == self.store._dict_cursor(mock_cursor)(*(1, 2, 3, 4))
 
-    @patch("oracledb.Cursor", autospec=True, spec_set=True, arraysize=5)
-    def test_output_type_handler(self, mock_cursor):
-        self.store._output_type_handler(mock_cursor, "name", oracledb.CLOB, 0, 0, 0)
-        mock_cursor.var.assert_called_with(oracledb.LONG_STRING, arraysize=5)
-
-        # some other type
-        result = self.store._output_type_handler(mock_cursor, "name", oracledb.NUMBER, 0, 0, 0)
-        assert result is None
-
     @patch("oracledb.Cursor", autospec=True, spec_set=True, arraysize=5, description=(("id",),))
     @patch("oracledb.Connection", autospec=True, spec_set=True)
     def test_query(self, mock_conn, mock_cursor):