mybatis插入數據（無則插入有則更新）以及字段自增

參考鏈接：

https://blog.csdn.net/hongtaolong/article/details/88343738

https://blog.csdn.net/definitly/article/details/82969245

https://www.runoob.com/mysql/mysql-index.html（MySQL 索引）

https://www.w3school.com.cn/sql/sql_unique.asp（SQL UNIQUE 約束）

https://blog.csdn.net/antony9118/article/details/72576199

<insert id="insertUser"  useGeneratedKeys="true" keyProperty="id" keyColumn="id"
            parameterType="com.foreigners.entity.User">
        insert INTO
        t_user(openId, name, gender, phoneNumber)
        VALUES
        (#{openId},#{name},#{gender},#{phoneNumber})
        ON DUPLICATE KEY UPDATE
        name = #{name},
        gender = #{gender},
        phoneNumber = #{phoneNumber}
</insert>

MySQL新增數據，存在就更新，不存在就添加（Mybatis）

https://blog.csdn.net/CNAHYZ/article/details/88786117