The table structure is unreasonable!

jue color table should be added

Add role fields to employee table

Character sheet

Employee list

Department table

Why is "mutual foreign key reference" a contradiction?

If you want to add a new department, and the manager of this department is also a new person, you can first use an old employee to "act" as the manager, and then modify it after the addition is successful. For example, adding a new financial department and manager Zhang San:

insert into 部门表 select id=财务部, manager=老王
insert into 职工表 select id=张三, department=财务部
update 部门表 set manager=张三 where id=财务部

The next question is, how to add when both tables are empty? At this time, you can add a row of data first and then add the foreign key constraints.