Documentdb Sql 简明教程

DocumentDB SQL - Array Creation

在 DocumentDB SQL 中，Microsoft 添加了一个关键功能，借助此功能我们可以轻松创建数组。这意味着当我们运行查询时，它将创建类似于 JSON 对象的集合数组作为查询的结果。

In DocumentDB SQL, Microsoft has added a key feature with the help of which we can easily create an array. It means when we run a query, then as a result it will create an array of collection similar to JSON object as a result of query.

让我们考虑与前例中相同的文档。

Let’s consider the same documents as in the previous examples.

以下是 AndersenFamily 文档。

Following is the AndersenFamily document.

{
   "id": "AndersenFamily",
   "lastName": "Andersen",

   "parents": [
      { "firstName": "Thomas", "relationship":  "father" },
      { "firstName": "Mary Kay", "relationship":  "mother" }
   ],

   "children": [
      {
         "firstName": "Henriette Thaulow",
         "gender": "female",
         "grade": 5,
         "pets": [ { "givenName": "Fluffy", "type":  "Rabbit" } ]
      }
   ],

   "location": { "state": "WA", "county": "King", "city": "Seattle" },
   "isRegistered": true
}

以下是 SmithFamily 文档。

Following is the SmithFamily document.

{
   "id": "SmithFamily",

   "parents": [
      { "familyName": "Smith", "givenName": "James" },
      { "familyName": "Curtis", "givenName": "Helen" }
   ],

   "children": [
      {
         "givenName": "Michelle",
         "gender": "female",
         "grade": 1
      },

      {
         "givenName": "John",
         "gender": "male",
         "grade": 7,

         "pets": [
            { "givenName": "Tweetie", "type": "Bird" }
         ]
      }
   ],

   "location": {
      "state": "NY",
      "county": "Queens",
      "city": "Forest Hills"
   },

   "isRegistered": true
}

以下是 WakefieldFamily 文档。

Following is the WakefieldFamily document.

{
   "id": "WakefieldFamily",

   "parents": [
      { "familyName": "Wakefield", "givenName": "Robin" },
      { "familyName": "Miller", "givenName": "Ben" }
   ],

   "children": [
      {
         "familyName": "Merriam",
         "givenName": "Jesse",
         "gender": "female",
         "grade": 6,

         "pets": [
            { "givenName": "Charlie Brown", "type": "Dog" },
            { "givenName": "Tiger", "type": "Cat" },
            { "givenName": "Princess", "type": "Cat" }
         ]
      },

      {
         "familyName": "Miller",
         "givenName": "Lisa",
         "gender": "female",
         "grade": 3,

         "pets": [
            { "givenName": "Jake", "type": "Snake" }
         ]
      }
   ],

   "location": { "state": "NY", "county": "Manhattan", "city": "NY" },
   "isRegistered": false
}

我们来看一个例子。

Let’s take a look at an example.

array creation

以下是将返回每个家庭的姓氏和地址的查询。

Following is the query which will return the family name and address of each family.

SELECT f.id AS FamilyName,
[f.location.city, f.location.county, f.location.state] AS Address
FROM Families f

可以看到 city、county 和 state 字段用方括号括起来，这将创建一个数组，此数组名为 Address。当执行上述查询时，它会生成以下输出。

As can be seen city, county and state fields are enclosed in square brackets, which will create an array and this array is named Address. When the above query is executed, it produces the following output.

[
   {
      "FamilyName": "WakefieldFamily",
      "Address": [
         "NY",
         "Manhattan",
         "NY"
      ]
   },

   {
      "FamilyName": "SmithFamily",
      "Address": [
         "Forest Hills",
         "Queens",
         "NY"
      ]
   },

   {
      "FamilyName": "AndersenFamily",
      "Address": [
         "Seattle",
         "King",
         "WA"
      ]
   }
]

在上述输出中，城市、县和州信息被添加到 Address 数组中。

The city, county, and state information are added in the Address array in the above output.