反轉MQL查詢

Question

Chapter 3 of the MQL reference（特別是第3.2.6節）討論顛倒查詢以獲得不同結構中的相同數據，以簡化查詢或按摩數據以返回與您自己類似的結構。

於是我開始用下面的查詢：

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

可讀的版本：

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

結果：

{ 
    "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" 
} 

但我想使查詢生成爲中心的，所以我修改它像這樣：

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

可讀的版本：

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

結果：

{ 
    "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" 
} 

我倒查詢只返回兩代人！請幫我弄清楚這是爲什麼。

Answer 1

如果您查看Automobile Generation的Freebase架構頁面，您會看到model屬性已被棄用，並被替換爲型號屬性。做出這樣的轉變對您的查詢：

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

帶給你預期的結果集：

[ 
    { 
    "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" 
    } 
]