Fixed additional scenarios where a query is re-executed with LOBs or

JSON columns after the underlying table is dropped and recreated.

Author: anthony-tuininga

doc/src/release_notes.rst

@@ -18,9 +18,9 @@ Thin Mode Changes
 #)  Replaced regular expressions for parsing SQL with regular expressions that
     perform better
     (`issue 172 <https://github.com/oracle/python-oracledb/issues/172>`__).
-#)  Fixed bug when a query is re-executed with the setting
-    ``oracledb.defaults.fetch_lobs = False`` after a table underlying the query
-    is dropped and recreated.
+#)  Fixed bug when a query is re-executed containing LOBs (either fetched as
+    LOB locators or as strings/bytes) or JSON data after a table underlying the
+    query is dropped and recreated.
 #)  Fixed bug when warning message is encountered during connect
     (`issue 171 <https://github.com/oracle/python-oracledb/issues/171>`__).
 

src/oracledb/impl/thin/cursor.pyx

@@ -96,7 +96,6 @@ cdef class ThinCursorImpl(BaseCursorImpl):
             if typ_impl.is_xml_type:
                 var_impl.outconverter = \
                         lambda v: v if isinstance(v, str) else v.read()
-        self._statement._always_full_execute = self._statement._requires_define
 
     cdef int _fetch_rows(self, object cursor) except -1:
         """

src/oracledb/impl/thin/messages.pyx

@@ -454,6 +454,7 @@ cdef class MessageWithData(Message):
             for i, var_impl in enumerate(cursor_impl.fetch_var_impls):
                 cursor_impl._create_fetch_var(conn, self.cursor, type_handler,
                                               i, var_impl._fetch_info)
+            cursor_impl._statement._adjust_requires_define()
             statement._last_output_type_handler = type_handler
 
         # the list of output variables is equivalent to the fetch variables
@@ -717,6 +718,7 @@ cdef class MessageWithData(Message):
                 self._adjust_fetch_info(prev_fetch_var_impls[i], fetch_info)
             cursor_impl._create_fetch_var(conn, self.cursor, type_handler, i,
                                           fetch_info)
+        cursor_impl._statement._adjust_requires_define()
         buf.read_ub4(&num_bytes)
         if num_bytes > 0:
             buf.skip_raw_bytes_chunked()    # current date

src/oracledb/impl/thin/statement.pyx

@@ -146,6 +146,18 @@ cdef class Statement:
             else:
                 self._bind_info_dict[info._bind_name] = [info]
 
+    cdef int _adjust_requires_define(self) except -1:
+        """
+        The define step is only supposed to be done once for each cursor, but a
+        full execute is required if a define was ever performed, so perform
+        that adjustment here, if needed.
+        """
+        if self._requires_define:
+            if self._always_full_execute:
+                self._requires_define = False
+            else:
+                self._always_full_execute = True
+
     cdef _determine_statement_type(self, str sql):
         """
         Determine the type of the SQL statement by examining the first keyword

tests/test_4300_cursor_other.py

@@ -914,7 +914,7 @@ def test_4369_bind_order_for_plsql(self):
             self.assertEqual(fetched_rows, rows)
 
     def test_4370_rebuild_table_with_lob_in_cached_query(self):
-        "4370 - test rebuild of table with LOB in cached query"
+        "4370 - test rebuild of table with LOB in cached query (as string)"
         table_name = "test_4370"
         drop_sql = f"drop table {table_name} purge"
         create_sql = f"""
@@ -945,5 +945,39 @@ def test_4370_rebuild_table_with_lob_in_cached_query(self):
             self.cursor.execute(query_sql)
             self.assertEqual(self.cursor.fetchall(), data)
 
+    def test_4371_rebuild_table_with_lob_in_cached_query(self):
+        "4371 - test rebuild of table with LOB in cached query (as LOB)"
+        table_name = "test_4371"
+        drop_sql = f"drop table {table_name} purge"
+        create_sql = f"""
+            create table {table_name} (
+                Col1 number(9) not null,
+                Col2 clob not null
+            )"""
+        insert_sql = f"insert into {table_name} values (:1, :2)"
+        query_sql = f"select * from {table_name} order by Col1"
+        data = [
+            (1, "CLOB value 1"),
+            (2, "CLOB value 2")
+        ]
+        try:
+            self.cursor.execute(drop_sql)
+        except:
+            pass
+        self.cursor.execute(create_sql)
+        self.cursor.executemany(insert_sql, data)
+        self.cursor.execute(query_sql)
+        fetched_data = [(n, c.read()) for n, c in self.cursor]
+        self.assertEqual(fetched_data, data)
+        self.cursor.execute(query_sql)
+        fetched_data = [(n, c.read()) for n, c in self.cursor]
+        self.assertEqual(fetched_data, data)
+        self.cursor.execute(drop_sql)
+        self.cursor.execute(create_sql)
+        self.cursor.executemany(insert_sql, data)
+        self.cursor.execute(query_sql)
+        fetched_data = [(n, c.read()) for n, c in self.cursor]
+        self.assertEqual(fetched_data, data)
+
 if __name__ == "__main__":
     test_env.run_test_cases()