Ember 数据嵌入 belongsTo 关系返回 null

Question

我有两个模型：

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，如果我打电话给answer.get('question')，我会得到空值。知道为什么会这样吗？

Answer 1

我认为你需要告诉 Ember 你的关系将被嵌入，这样做是这样的。

Question = DS.Model.extend

  answers: DS.hasMany("answer", embedded: 'always')

Answer = DS.Model.extend

  question: DS.belongsTo("question", embedded: 'always')

话虽如此，您可能需要重新考虑您的 json 结构，嵌入式记录会导致大量重复。

Ember 期望以下开箱即用。

{
  "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') 有效，您只需升级到 Ember Data beta.10，它增加了对双方关系的支持。