grails - 为连接到另一个域的复合主键的外键创建 Grails 域映射

Question

如何将 Grails 域的两列(也是其复合主键)引用到另一个域类的复合主键？在这种情况下，CEO 之间存在一对一的关系。至Agency和 Agency至Branch .

我可以轻松映射CEO至Agency因为它只涉及一列:CEO.id == Agency.ceo_id .但我无法映射Branch至Agency使用这两列:Agency.id == Branch.agency_id and Agency.main_branch_id == Branch.branch_id .

class CEO {
    .....
}

class Agency {
    .....
    CEO ceo
    Branch mainBranch

    static mapping = {
        .....
        ceo column: 'ceo_id'
        /* Tried using this mapping but it doesn't work
        mainBranch {
            agencyId column: 'id',
            branchId column: 'main_branch_id'
        }
        */
        .....
    }
}

class Branch {
    .....
    Integer agencyId
    Integer branchId

    static mapping = {
        .....
        id composite: ['agencyId', 'branchId']
        .....
    }

    static constraints = {
        .....
        branchId unique: 'agencyId'
        .....
    }
}

Answer 1

请尝试对代理类使用以下技术:

 class Agency {
     .....
     CEO ceo
     Branch mainBranch

     static mapping = {
     .....
     ceo column: 'ceo_id'
     columns {
        mainBranch {
            column name: "FirstName"
            column name: "LastName"
        }
     }
 .....
 }

引用是 here - 第 6.5.2.5 节复合主键。