Fixed bug when using bind variables with scrollable cursors.

Author: anthony-tuininga

doc/src/release_notes.rst

@@ -19,6 +19,8 @@ oracledb `3.5.0 <https://github.com/oracle/python-oracledb/compare/v3.4.0...v3.5
 Thin Mode Changes
 +++++++++++++++++
 
+#)  Fixed bug when using bind variables with scrollable cursors.
+
 Thick Mode Changes
 ++++++++++++++++++
 

src/oracledb/impl/thin/constants.pxi

@@ -240,6 +240,7 @@ cdef enum:
 cdef enum:
     TNS_EXEC_FLAGS_DML_ROWCOUNTS = 0x4000
     TNS_EXEC_FLAGS_IMPLICIT_RESULTSET = 0x8000
+    TNS_EXEC_FLAGS_NO_CANCEL_ON_EOF = 0x80
     TNS_EXEC_FLAGS_SCROLLABLE = 0x02
 
 # fetch orientations

src/oracledb/impl/thin/cursor.pyx

@@ -72,7 +72,7 @@ cdef class BaseThinCursorImpl(BaseCursorImpl):
         message.num_execs = 1
         if self.scrollable:
             message.fetch_orientation = TNS_FETCH_ORIENTATION_CURRENT
-            message.fetch_pos = 1
+            message.fetch_pos = self.rowcount + 1
         return message
 
     cdef ExecuteMessage _create_scroll_message(self, object cursor,
@@ -116,7 +116,7 @@ cdef class BaseThinCursorImpl(BaseCursorImpl):
 
         # build message
         message = self._create_message(ExecuteMessage, cursor)
-        message.scroll_operation = self._more_rows_to_fetch
+        message.scroll_operation = True
         message.fetch_orientation = orientation
         message.fetch_pos = <uint32_t> desired_row
         return message
@@ -259,8 +259,8 @@ cdef class ThinCursorImpl(BaseThinCursorImpl):
         cdef:
             Protocol protocol = <Protocol> self._conn_impl._protocol
             MessageWithData message
-        if self._statement._sql is None:
-            message = self._create_message(ExecuteMessage, cursor)
+        if self._statement._sql is None or self.scrollable:
+            message = self._create_execute_message(cursor)
         else:
             message = self._create_message(FetchMessage, cursor)
         protocol._process_single_message(message)
@@ -357,8 +357,8 @@ cdef class AsyncThinCursorImpl(BaseThinCursorImpl):
         Internal method used for fetching rows from the database.
         """
         cdef MessageWithData message
-        if self._statement._sql is None:
-            message = self._create_message(ExecuteMessage, cursor)
+        if self._statement._sql is None or self.scrollable:
+            message = self._create_execute_message(cursor)
         else:
             message = self._create_message(FetchMessage, cursor)
         await self._conn_impl._protocol._process_single_message(message)

src/oracledb/impl/thin/messages/execute.pyx

@@ -83,6 +83,7 @@ cdef class ExecuteMessage(MessageWithData):
                 options |= TNS_EXEC_OPTION_EXECUTE
         if cursor_impl.scrollable and not self.parse_only:
             exec_flags |= TNS_EXEC_FLAGS_SCROLLABLE
+            exec_flags |= TNS_EXEC_FLAGS_NO_CANCEL_ON_EOF
         if stmt._cursor_id == 0 or stmt._is_ddl:
             options |= TNS_EXEC_OPTION_PARSE
         if stmt._is_query:
@@ -100,7 +101,7 @@ cdef class ExecuteMessage(MessageWithData):
             options |= TNS_EXEC_OPTION_NOT_PLSQL
         elif stmt._is_plsql and num_params > 0:
             options |= TNS_EXEC_OPTION_PLSQL_BIND
-        if num_params > 0:
+        if num_params > 0 and not self.scroll_operation:
             options |= TNS_EXEC_OPTION_BIND
         if self.batcherrors:
             options |= TNS_EXEC_OPTION_BATCH_ERRORS

tests/test_4200_cursor_scrollable.py

@@ -246,3 +246,22 @@ def test_4215(conn):
     cursor.scroll(mode="last")
     (fetched_value,) = cursor.fetchone()
     assert fetched_value == 5
+
+
+def test_4216(conn):
+    "4216 - test scroll operation with bind values"
+    cursor = conn.cursor(scrollable=True)
+    base_value = 4215
+    cursor.execute(
+        """
+        select :base_value + 1 from dual
+        union all
+        select :base_value + 2 from dual
+        union all
+        select :base_value + 3 from dual
+        """,
+        dict(base_value=base_value),
+    )
+    cursor.scroll(mode="last")
+    (fetched_value,) = cursor.fetchone()
+    assert fetched_value == base_value + 3

tests/test_8600_cursor_scrollable_async.py

@@ -249,3 +249,22 @@ async def test_8615(async_conn):
     await cursor.scroll(mode="last")
     (fetched_value,) = await cursor.fetchone()
     assert fetched_value == 5
+
+
+async def test_8616(async_conn):
+    "8616 - test scroll operation with bind values"
+    cursor = async_conn.cursor(scrollable=True)
+    base_value = 4215
+    await cursor.execute(
+        """
+        select :base_value + 1 from dual
+        union all
+        select :base_value + 2 from dual
+        union all
+        select :base_value + 3 from dual
+        """,
+        dict(base_value=base_value),
+    )
+    await cursor.scroll(mode="last")
+    (fetched_value,) = await cursor.fetchone()
+    assert fetched_value == base_value + 3