两个表之间可以有两个关系吗? [英] Can there be two relationships between two tables?

问题描述

有两个表:EMPLOYER和EMPLOYEE.由于每个雇员都分配给一个雇员，因此它们之间是1:N的关系-简单的东西. 但是我还希望能够建立一个模型，在这种情况下，每个雇员都可以选择他的一个最喜欢的雇员(他也可以不选择任何一个).

There are two tables: EMPLOYER and EMPLOYEE. Since each EMPLOYEE is assigned to one EMPLOYER there's 1:N relationship between them - simple stuff. But I also want to be able to model a situation where each EMPLOYER may be able to choose his one favorite EMPLOYEE (he might as well choose none).

我也应该:
1.在这些表之间添加第二个1:1关系-这样EMPLOYER还将包含EMPLOYEE_id_FK. 两个表之间是否允许两个关系?
2.添加由两个唯一的主键-EMPLOYER_ID和EMPLOYEE_ID标识的第三个表FAV.这样，我可以确定每个雇主只能有一个最喜欢的雇员，并且每个雇员也只能被一名雇员选为最喜欢的人-这正是我想要的.

So should I:
1. Add a second 1:1 relationship between those tables - this way EMPLOYER would also contain EMPLOYEE_id_FK. Is having two relationship between two tables even allowed?
2. Add a third table FAV identified by two primary, unique keys - EMPLOYER_ID and EMPLOYEE_ID? This way I would be sure each employer could only have one favorite employee and also each employee may be chosen as a fav only by one employee - which is exactly what I wanted.

做这件事的正确方法是什么?

What's the proper way to do it?

推荐答案

我的建议是拥有四个表.一个雇员表，一个雇主表，一个将雇员与雇主联系起来的表(谁说一个雇员不能为两个雇主工作)，最后是一个将雇主与自己喜欢的雇员联系起来的表.

My recommendation is to have four table. One employee table, one employer table, a table to relate employee to employer (who says an employee can't work for two employers), and finally a table to relate an employer to their favorite employee.

是的，当然，在两个表之间可以有两个关系.

Yes, of course there can be two relationships between the same two tables.

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