feat: remove adding a dummy WHERE clause into UPDATE and DELETE statements (#169)

* feat: don't add dummy WHERE clause into UPDATE and DELETE queries

* fix docstrings

Author: Ilya Gurov

google/cloud/spanner_dbapi/parse_utils.py

@@ -523,11 +523,19 @@ def get_param_types(params):
 def ensure_where_clause(sql):
     """
     Cloud Spanner requires a WHERE clause on UPDATE and DELETE statements.
-    Add a dummy WHERE clause if necessary.
+    Raise an error, if the given sql doesn't include it.
+
+    :type sql: `str`
+    :param sql: SQL code to check.
+
+    :raises: :class:`ProgrammingError` if the given sql doesn't include a WHERE clause.
     """
     if any(isinstance(token, sqlparse.sql.Where) for token in sqlparse.parse(sql)[0]):
         return sql
-    return sql + " WHERE 1=1"
+
+    raise ProgrammingError(
+        "Cloud Spanner requires a WHERE clause when executing DELETE or UPDATE query"
+    )
 
 
 def escape_name(name):

tests/unit/spanner_dbapi/test_cursor.py

@@ -100,7 +100,7 @@ def test_do_execute_update(self):
         def run_helper(ret_value):
             transaction.execute_update.return_value = ret_value
             res = cursor._do_execute_update(
-                transaction=transaction, sql="sql", params=None
+                transaction=transaction, sql="SELECT * WHERE true", params={},
             )
             return res
 

tests/unit/spanner_dbapi/test_parse_utils.py

@@ -391,36 +391,26 @@ def test_get_param_types_none(self):
 
     @unittest.skipIf(skip_condition, skip_message)
     def test_ensure_where_clause(self):
+        from google.cloud.spanner_dbapi.exceptions import ProgrammingError
         from google.cloud.spanner_dbapi.parse_utils import ensure_where_clause
 
-        cases = [
-            (
-                "UPDATE a SET a.b=10 FROM articles a JOIN d c ON a.ai = c.ai WHERE c.ci = 1",
-                "UPDATE a SET a.b=10 FROM articles a JOIN d c ON a.ai = c.ai WHERE c.ci = 1",
-            ),
-            (
-                "UPDATE (SELECT * FROM A JOIN c ON ai.id = c.id WHERE cl.ci = 1) SET d=5",
-                "UPDATE (SELECT * FROM A JOIN c ON ai.id = c.id WHERE cl.ci = 1) SET d=5 WHERE 1=1",
-            ),
-            (
-                "UPDATE T SET A = 1 WHERE C1 = 1 AND C2 = 2",
-                "UPDATE T SET A = 1 WHERE C1 = 1 AND C2 = 2",
-            ),
-            (
-                "UPDATE T SET r=r*0.9 WHERE id IN (SELECT id FROM items WHERE r / w >= 1.3 AND q > 100)",
-                "UPDATE T SET r=r*0.9 WHERE id IN (SELECT id FROM items WHERE r / w >= 1.3 AND q > 100)",
-            ),
-            (
-                "UPDATE T SET r=r*0.9 WHERE id IN (SELECT id FROM items WHERE r / w >= 1.3 AND q > 100)",
-                "UPDATE T SET r=r*0.9 WHERE id IN (SELECT id FROM items WHERE r / w >= 1.3 AND q > 100)",
-            ),
-            ("DELETE * FROM TABLE", "DELETE * FROM TABLE WHERE 1=1"),
-        ]
+        cases = (
+            "UPDATE a SET a.b=10 FROM articles a JOIN d c ON a.ai = c.ai WHERE c.ci = 1",
+            "UPDATE T SET A = 1 WHERE C1 = 1 AND C2 = 2",
+            "UPDATE T SET r=r*0.9 WHERE id IN (SELECT id FROM items WHERE r / w >= 1.3 AND q > 100)",
+        )
+        err_cases = (
+            "UPDATE (SELECT * FROM A JOIN c ON ai.id = c.id WHERE cl.ci = 1) SET d=5",
+            "DELETE * FROM TABLE",
+        )
+        for sql in cases:
+            with self.subTest(sql=sql):
+                ensure_where_clause(sql)
 
-        for sql, want in cases:
+        for sql in err_cases:
             with self.subTest(sql=sql):
-                got = ensure_where_clause(sql)
-                self.assertEqual(got, want)
+                with self.assertRaises(ProgrammingError):
+                    ensure_where_clause(sql)
 
     @unittest.skipIf(skip_condition, skip_message)
     def test_escape_name(self):