diff --git a/gluon/dal/adapters/base.py b/gluon/dal/adapters/base.py
index aad58af9..050edb68 100644
--- a/gluon/dal/adapters/base.py
+++ b/gluon/dal/adapters/base.py
@@ -76,7 +76,8 @@ class BaseAdapter(ConnectionPool):
     dbpath = None
     folder = None
     connector = lambda *args, **kwargs: None # __init__ should override this
-
+    TRUE_exp = '1'
+    FALSE_exp = '0'
     TRUE = 'T'
     FALSE = 'F'
     T_SEP = ' '
@@ -909,7 +910,7 @@ class BaseAdapter(ConnectionPool):
             return ','.join(self.represent(item,field_type) \
                                 for item in expression)
         elif isinstance(expression, bool):
-            return '1' if expression else '0'
+            return self.db._adapter.TRUE_exp if expression else self.db._adapter.FALSE_exp
         else:
             return str(expression)
 
diff --git a/gluon/dal/adapters/postgres.py b/gluon/dal/adapters/postgres.py
index 7e81d6c8..7e8c32fd 100644
--- a/gluon/dal/adapters/postgres.py
+++ b/gluon/dal/adapters/postgres.py
@@ -104,7 +104,8 @@ class PostgreSQLAdapter(BaseAdapter):
         self.srid = srid
         self.find_or_make_work_folder()
         self._last_insert = None # for INSERT ... RETURNING ID
-        
+        self.TRUE_exp = 'TRUE'
+        self.FALSE_exp = 'FALSE'
         ruri = uri.split('://',1)[1]
         m = self.REGEX_URI.match(ruri)
         if not m: