-- Invalidate slide challenges before restoring the previous constraint.
UPDATE login_captcha_policy SET saas_mode='image',version=version+1,updated_at=now()
  WHERE saas_mode='slide';
ALTER TABLE login_captcha_policy DROP CONSTRAINT login_captcha_policy_saas_mode_check;
ALTER TABLE login_captcha_policy ADD CONSTRAINT login_captcha_policy_saas_mode_check
  CHECK (saas_mode IN ('image','tencent'));