如何在三个域类之间建立多个一对一关系 [英] How to have multiple One-to-One relationships between three domain classes

问题描述

作为这个的后续问题，我想要一个用户 domain类，它与 BasicProfile 域类具有可选的一对一关系，用户是所有者其中可能有也可能没有配置文件。我有这方面的想法。我还想要的是 AcademicProfile 域类与 User 之间的可选一对一关系， AcademicProfile 作为所有者，因此 AcademicProfile 可能有也可能没有 User 。当我尝试按照我做第一对一关系的方式进行复制时，它不起作用。

As a follow up question to this, I want to have a User domain class which has an optional one-to-one relationship with BasicProfile domain class, User being the owner which may or may not have a profile. I have this part figured out. What I also want is an optional one-to-one relationship between the AcademicProfile domain class and the User, AcademicProfile being the owner, such that an AcademicProfile may or may not have a User. When I try to replicate this the way I did the first one-to-one relationship, it does not work. Here are my classes.

class User {

    String username
    String password
    String email
    AcademicProfile academicProfile
    Date dateCreated
    Date lastUpdated

    static hasOne = [basicProfile: BasicProfile]

    static constraints = {
        username size: 3..20, unique: true, nullable: false, validator: { _username ->
            _username.toLowerCase() == _username
        }
        password size: 6..100, nullable: false, validator: { _password, user ->
            _password != user.username
        }
        email email: true, blank: false
        basicProfile nullable: true
    }
}

class BasicProfile extends Profile {

    User user
    Date dateCreated
    Date lastUpdated

}

class AcademicProfile extends Profile {

    String dblpId
    String scholarId
    String website
    Date dateCreated
    Date lastUpdated

    static hasOne = [user: User]
    static hasMany = [publications: Publication]

    static constraints = {
        dblpId nullable: true
        scholarId nullable: true
        website nullable: true, url: true
        publications nullable: true
        user nullable: true
    }
}

class Profile {
    String firstName
    String middleName
    String lastName
    byte[] photo
    String bio

    static constraints = {
        firstName blank: false
        middleName nullable: true
        lastName blank: false
        photo nullable: true, maxSize: 2 * 1024**2
        bio nullable: true, maxSize: 500
    }

    static mapping = {
        tablePerSubclass true
    }
}

当我运行它时，出现以下错误：字段'academicProfile'中对象'org.academic.User'中的字段错误：被拒绝的值[null]; 。我不明白我在做什么错误。

When I run it, I get the error: Field error in object 'org.academic.User' on field 'academicProfile': rejected value [null];. I don't understand what I am doing wrong.

推荐答案

您必须添加 nullable：对于 AcademicProfile academicProfile 在用户类中的真实约束，您提到您需要AcademicProfile& User。

You'll have to add nullable:true constraint for AcademicProfile academicProfile in User class as you mentioned that you need an 'optional' relationship between AcademicProfile & User.

这个错误本身就是一个自我解释，你不能创建一个User类的实例，但不提供academicProfile属性的非空值。

The error itself is self explanatory though, that you can't create a User class's instance, without providing the academicProfile property a non-null value.

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