-- 修复答案保存问题
-- 唯一索引 uk_assessment_item 已存在，无需再创建

-- 验证索引
SHOW INDEX FROM psy_assessment_answer;

-- 如果有重复数据需要清理，可以执行以下语句（可选）：
-- DELETE a FROM psy_assessment_answer a
-- INNER JOIN psy_assessment_answer b
-- WHERE a.assessment_id = b.assessment_id 
--   AND a.item_id = b.item_id 
--   AND a.answer_id < b.answer_id;