Grails-[1：N]关系问题

Question

I have 2 different domain classes, one for Employee and one for Departments. The relationship between them is [1:N],which means that many employees can work at one Department but not vice versa. The issue is that, after Grails creates the tables from the domain classes when the project runs, for one employee, the department Id of that table references the id on Department Table. For example, for a user named "Peter", department id would be 1.

The department table also has names for the departments, along with the department id's.

How can I reference the department_id in employee table to point at department.name instead of department.id ?

Department Domain Class :

class Department {
    String name

    static hasMany = [
            employees: Employee
    ]

    static constraints = {
    }

    static mapping = {
        version false
    }

    def String toString() {
        name
    }


}

Employee Domain Class :

class Employee {
    String firstName
    String lastName
    String email
    String country
    int born

    static belongsTo = [department: Department]

    static constraints = {
        firstName(blank: false)
        lastName(blank: false)
        born(blank: false)
        email(blank: false, email: true)
        country(blank: false)
    }

    static mapping = {
        version false
    }
}

What I need is, when in Employee table, the department_id column to reference at department.name instead of department.id.

Answer 1

I guess you need to configure that the Primary Key of the Department table is 'name' instead of the default 'id' column. Grails will then use the name as the Foreign Key.

ie:

class Department {
...
    static mapping = {
        id name: 'name'
    }
...
}

ref (Grails 3.1) : http://docs.grails.org/3.1.x/ref/Database%20Mapping/id.html