SQLAlchemy: Fix SQL statement caching for CrateDB's OBJECT type

The SQLAlchemy implementation of CrateDB's `OBJECT` type offers indexed
access to the instance's content in form of a dictionary. Thus, it must
not use `cache_ok = True` on its implementation, i.e. this part of the
compiled SQL clause must not be cached.

Author: amotl

CHANGES.txt

@@ -13,6 +13,8 @@ Unreleased
 
 - Allow handling datetime values tagged with time zone info when inserting or updating.
 
+- SQLAlchemy: Fix SQL statement caching for CrateDB's ``OBJECT`` type.
+
 
 2023/04/18 0.31.1
 =================

src/crate/client/sqlalchemy/types.py

@@ -132,7 +132,7 @@ def __eq__(self, other):
 
 
 class _Craty(sqltypes.UserDefinedType):
-    cache_ok = True
+    cache_ok = False
 
     class Comparator(sqltypes.TypeEngine.Comparator):