-- ============================================
-- V21: 为 member_card_transactions 表添加 updated_at 字段
-- 原因：MemberCardTransaction 继承 BaseEntity 已映射该字段，但表缺失
-- ============================================

ALTER TABLE member_card_transactions
    ADD COLUMN IF NOT EXISTS updated_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP;

COMMENT ON COLUMN member_card_transactions.updated_at IS '更新时间';
