Grails数据绑定疑问

Question

   Class Carro {
String name
String marca
String matricula

} 

Class CarroMovel{

String pro1
String prop2
String prop3

Carro carro

static hasMany = [ carros: Carro]

}

---

 def save2 = {

                def carroInstance = new Carro()
                def carroMovelInstance = new CarroMovel()

                carroInstance.name = params.name
                carroInstance.marca = params.marca
                carroInstance.matricula = params.matricula

                carroMovelInstance.prop1 = params.carroMovel.prop1
                carroMovelInstance.prop2 = params.carroMovel.prop2
                carroMovelInstance.prop3 = params.carroMovel.prop3

                carroInstance.save()
                carroMovelInstance.carro = carroInstance
                carroMovelInstance.save()                 

            }

CarroInstance 正在保存，但 carroMovelInstance 没有保存。我无法弄清楚。任何帮助将不胜感激。

Answer 1

Grooveek 是正确的，因为您从未调用过 carroMovelInstance.save( ）。

然而，对您来说，简单地利用 Grails 的数据绑定可能会更简单，而不是不必要地创建关联并手动绑定参数。

// Update your Carro domain.
def Carro {
    String name
    String marca
    String matricula

    // will cause persistence operations to cascade from CarroMovel to Carro
    static belongsTo = CarroMovel
}

// Update your save2 action.
// By passing 'params' to the CarroMovel constructor, Grails will bind request
// parameters to domain properties of the same name; it even works with associations!
def save2 = {
    def carroMovelInstance = new CarroMovel(params)
    if(carroMovelInstance.validate) {
        carroMovelInstance.save()
    }
}

阅读 Grails 数据绑定，特别是关联部分。此外，请阅读"了解级联更新和删除" 了解如何对父域对象调用 save() 将（或不会）级联到关联的域对象。

Answer 2

你从不要求 carroMovelInstance 保存... carro 实例也没有引用 carroMovel 实例，因此没有级联保存