让mysql的id字段变成表的主键
1.#已经加主键
desc szdj.sys_message_user;
alter table sys_message_user add constraint pk_mess_user primary key(id);
给约束起名:pk_mess_user
用一个例子来演示会更加清晰
1.#已经加主键
desc szdj.sys_message_user;
alter table sys_message_user add constraint pk_mess_user primary key(id);
给约束起名:pk_mess_user