反转MQL查询

Question

Chapter 3 of the MQL reference (特别是第3.2.6节)讨论了反向查询以获得不同结构中的相同数据，以简化查询或修改数据以返回与您自己的结构相似的结构。

因此，我从下面的查询开始：

https://api.freebase.com/api/service/mqlread?query={"query":{"type":"/automotive/model","name":"Ford Taurus","generations":[]}}

可读版本：

{
    "type":"/automotive/model",
    "name":"Ford Taurus",
    "generations":[]
}

结果：

{
  "code": "/api/status/ok",
  "result": {
    "generations": [
      "First Generation Ford Taurus",
      "Second Generation Ford Taurus",
      "Fifth Generation Ford Taurus",
      "Sixth Generation Ford Taurus",
      "Fourth Generation Ford Taurus",
      "Third Generation Ford Taurus"
    ],
    "name": "Ford Taurus",
    "type": "/automotive/model"
  },
  "status": "200 OK",
  "transaction_id": "cache;cache04.p01.sjc1:8101;2013-04-25T22:05:58Z;0012"
}

但是我想让查询以生成为中心，所以我这样修改它：

https://api.freebase.com/api/service/mqlread?query={"query":[{"type":"/automotive/generation","model":"Ford Taurus","name":null}]}

可读版本：

[{
    "type":"/automotive/generation",
    "model":"Ford Taurus",
    "name":null
}]

结果：

{
  "code": "/api/status/ok",
  "result": [
    {
      "model": "Ford Taurus",
      "name": "First Generation Ford Taurus",
      "type": "/automotive/generation"
    },
    {
      "model": "Ford Taurus",
      "name": "Third Generation Ford Taurus",
      "type": "/automotive/generation"
    }
  ],
  "status": "200 OK",
  "transaction_id": "cache;cache01.p01.sjc1:8101;2013-04-25T23:00:35Z;0010"
}

我的反向查询只返回两代！请帮我弄清楚为什么会这样。

Answer 1

如果您查看Automobile Generation的Freebase模式页面，您将看到model属性已被弃用，并被models的属性所取代。对您的查询进行此更改：

[{
  "type": "/automotive/generation",
  "models": "Ford Taurus",
  "name": null
}]

为您提供预期的结果集：

[
  {
    "models": "Ford Taurus",
    "name": "First Generation Ford Taurus",
    "type": "/automotive/generation"
  },
  {
    "models": "Ford Taurus",
    "name": "Second Generation Ford Taurus",
    "type": "/automotive/generation"
  },
  {
    "models": "Ford Taurus",
    "name": "Fifth Generation Ford Taurus",
    "type": "/automotive/generation"
  },
  {
    "models": "Ford Taurus",
    "name": "Sixth Generation Ford Taurus",
    "type": "/automotive/generation"
  },
  {
    "models": "Ford Taurus",
    "name": "Fourth Generation Ford Taurus",
    "type": "/automotive/generation"
  },
  {
    "models": "Ford Taurus",
    "name": "Third Generation Ford Taurus",
    "type": "/automotive/generation"
  }
]