diff --git a/addons/mail/mail_followers.py b/addons/mail/mail_followers.py
index 255b6d55a50..0c9a1a65432 100644
--- a/addons/mail/mail_followers.py
+++ b/addons/mail/mail_followers.py
@@ -64,22 +64,12 @@ class mail_notification(osv.Model):
         'read': False,
     }
 
-    def init(self, cr):
-        """ Set a postgresql NOT NULL constraint with default value false for
-            the read column. The reason is that when writing in this table using
-            partner_ids of mail.message model, it bypasses the ORM default
-            values, leading to 'None' values for read field. This broke the
-            needaction mechanism for mail.message. """
-        cr.execute("ALTER TABLE mail_notification ALTER read SET NOT NULL")
-        cr.execute("ALTER TABLE mail_notification ALTER read SET DEFAULT false")
-
     def create(self, cr, uid, vals, context=None):
         """ Override of create to check that we can not create a notification
             for a message the user can not read. """
         if self.pool.get('mail.message').check_access_rights(cr, uid, 'read'):
             return super(mail_notification, self).create(cr, uid, vals, context=context)
-        else:
-            return False
+        return False
 
     def notify(self, cr, uid, partner_ids, msg_id, context=None):
         """ Send by email the notification depending on the user preferences """
diff --git a/addons/mail/mail_message.py b/addons/mail/mail_message.py
index 6c47e0006c9..97473886e1a 100644
--- a/addons/mail/mail_message.py
+++ b/addons/mail/mail_message.py
@@ -78,14 +78,15 @@ class mail_message(osv.Model):
     def _search_unread(self, cr, uid, obj, name, domain, context=None):
         """ Search for messages unread by the current user. """
         read_value = not domain[0][2]
+        read_cond = '' if read_value else '!= true'
         partner_id = self.pool.get('res.users').browse(cr, uid, uid, context=context).partner_id.id
         cr.execute("""  SELECT mail_message.id \
                         FROM mail_message \
                         JOIN mail_notification ON ( \
                             mail_notification.message_id = mail_message.id ) \
-                        WHERE mail_notification.partner_id = %s AND \
-                            mail_notification.read = %s \
-                    """ % (partner_id, read_value) )
+                        WHERE mail_notification.partner_id = %%s AND \
+                            mail_notification.read %s \
+                    """ % read_cond, (partner_id,) )
         res = cr.fetchall()
         message_ids = [r[0] for r in res]
         return [('id', 'in', message_ids)]