GORM如何确保相关对象属性的唯一性 [英] GORM how to ensure uniqueness of related objects property

问题描述

我试图让我的头部围绕GORM和关系映射。关系工作正常，但有一个问题。我似乎无法确保每个 MailAddress 添加到 MailingList 都有一个唯一的地址。注意：在 MailAddress.address上没有唯一的约束。

  class MailAddress {
 
字符串名称
字符串电子邮件
 
 static belongsTo = MailingList 
 
静态约束= {
姓名空白：true 
电子邮件电子邮件地址：true，blank：false 
 } 
} 
 
 class MailingList {
 
字符串名称
 
 static hasMany = [地址：MailAddress] 
 
静态映射= {
地址cascade：'all-delete-orphan'
} 
 
静态约束= {
空白名称：false 
} 
 
  

解决方案

ibaralf的答案是一个自定义验证器。
MailingList 类用于验证所有地址（ MailAddress ）是否具有唯一的电子邮件地址。 / p>

我将这个约束添加到 MailingList 类中并且它工作正常。

 静态约束= {
空白名称：false 
 
地址（验证者：{
 
 if（！it ）{
 //如果集合为空，则验证为TRUE 
 //防止NULL异常
返回true 
} 
 
 //获取集合列表中的所有电子邮件地址
 def addressCollection = it * .email 
 //与仅具有唯一地址的集合比较
 return addressCollection == addressCollection.unique（）
} ）
} 
  

更多信息可以在这里找到 http://grails.org/doc/2.2.0/ref/Constraints/validato r.html

I'm trying to get my head around GORM and relational mapping. The relationships are working fine but there is one problem. I can't seem too ensure that every MailAddress added to MailingList has a unique address. What would be the must efficient way to do this?

Note: There is no unique constraint on MailAddress.address. Identical addresses can exist in the same table.

class MailAddress {

    String name
    String email

    static belongsTo = MailingList

    static constraints = {
        name blank:true
        email email:true, blank:false
    }
}

class MailingList {

    String name

    static hasMany = [addresses:MailAddress]

    static mapping = {
        addresses cascade: 'all-delete-orphan'
    }

    static constraints = {
        name blank:false
    }
}

解决方案

As mentioned in the comments by @ibaralf the answer is a custom validator. The MailingList class needed to validate if all addresses (MailAddress) have a unique e-mailaddress.

I added this constraint to the MailingList class and it worked.

static constraints = {
    name blank:false

    addresses(validator: {

        if (!it) {
            // validates to TRUE if the collection is empty
            // prevents NULL exception
            return true
        }

        // Grab a collection with all e-mailaddresses in the list
        def addressCollection = it*.email
        // Compare to a collection with only unique addresses
        return addressCollection == addressCollection.unique()
    })
}

More info can be found here http://grails.org/doc/2.2.0/ref/Constraints/validator.html

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