Ember嵌入belongsTo关系的数据返回null

Question

我有两种型号：

Question = DS.Model.extend
  answers: DS.hasMany("answer")
Answer = DS.Model.extend
  question: DS.belongsTo("question")

json提供嵌入问题中的答案：

"questions": [{
  "id":"1.04"
  "text":"What is the position or title of the 1% who is being protested against?",
  "answers":[
    {
      "text":"City mayor",
      "id":"1.04.02"
    },
    {
      "text":"City council member",
      "id":"1.04.03"
    },
    {
      "text":"CEO of some company",
      "id":"1.04.01"
    }
  ]
}]

当我调用question.get('answers')时，Ember返回预期的答案数组。但是，如果我调用answer.get('question')，则会得到null。知道为什么会发生这种事吗？

Answer 1

我认为你需要告诉Ember你的关系将被嵌入，这是这样做的。

Question = DS.Model.extend
  answers: DS.hasMany("answer", embedded: 'always')
Answer = DS.Model.extend
  question: DS.belongsTo("question", embedded: 'always')

话虽如此，您可能需要重新思考您的json结构，嵌入的记录会引起很多重复。

Ember期待着以下的开箱即用。

{
  "questions": [
    {
      "id": "1.04"
      "text": "What is the position or title of the 1% who is being protested against?"
      "answer_ids": ["1.04.02", "1.04.03", "1.04.01"]
    }
  ],
  "answers": [
    {
      "text": "City mayor",
      "id": "1.04.02",
      "question_id": "1.04"
    },
    {
      "text": "City council member",
      "id": "1.04.03",
      "question_id": "1.04"
    },
    {
      "text": "CEO of some company",
      "id": "1.04.01",
      "question_id": "1.04"
    }
  ]
}

Answer 2

假设您的question.get('answers')可以工作，您只需要升级到Ember Data beta 10，它增加了对双方关系的支持。