使用适用于 MongoDB 的 Azure Cosmos DB 查询数据
适用对象: MongoDB
Azure Cosmos DB 的用于 MongoDB 的 API 支持 MongoDB 查询。
本文涵盖以下任务:
- 使用 MongoDB shell 查询存储在 Azure Cosmos DB 数据库中的数据
可以使用本文中的示例来快速入门。
示例文档
本文中的查询使用下面的示例文档。
{
"id": "WakefieldFamily",
"parents": [
{ "familyName": "Wakefield", "givenName": "Robin" },
{ "familyName": "Miller", "givenName": "Ben" }
],
"children": [
{
"familyName": "Merriam",
"givenName": "Jesse",
"gender": "female", "grade": 1,
"pets": [
{ "givenName": "Goofy" },
{ "givenName": "Shadow" }
]
},
{
"familyName": "Miller",
"givenName": "Lisa",
"gender": "female",
"grade": 8 }
],
"address": { "state": "NY", "county": "Manhattan", "city": "NY" },
"creationDate": 1431620462,
"isRegistered": false
}
示例查询 1
在示例家庭文档中,以下查询返回 id
字段匹配 WakefieldFamily
的文档。
查询:
db.families.find({ id: "WakefieldFamily"})
结果:
{
"_id": "ObjectId(\"58f65e1198f3a12c7090e68c\")",
"id": "WakefieldFamily",
"parents": [
{
"familyName": "Wakefield",
"givenName": "Robin"
},
{
"familyName": "Miller",
"givenName": "Ben"
}
],
"children": [
{
"familyName": "Merriam",
"givenName": "Jesse",
"gender": "female",
"grade": 1,
"pets": [
{ "givenName": "Goofy" },
{ "givenName": "Shadow" }
]
},
{
"familyName": "Miller",
"givenName": "Lisa",
"gender": "female",
"grade": 8
}
],
"address": {
"state": "NY",
"county": "Manhattan",
"city": "NY"
},
"creationDate": 1431620462,
"isRegistered": false
}
示例查询 2
下一个查询返回该家庭中的所有子女。
查询:
db.families.find( { id: "WakefieldFamily" }, { children: true } )
结果:
{
"_id": "ObjectId("58f65e1198f3a12c7090e68c")",
"children": [
{
"familyName": "Merriam",
"givenName": "Jesse",
"gender": "female",
"grade": 1,
"pets": [
{ "givenName": "Goofy" },
{ "givenName": "Shadow" }
]
},
{
"familyName": "Miller",
"givenName": "Lisa",
"gender": "female",
"grade": 8
}
]
}
示例查询 3
下一个查询返回所有已注册的家庭。
查询:
db.families.find( { "isRegistered" : true })
结果:
不返回任何文档。
示例查询 4
下一个查询返回所有未注册的家庭。
查询:
db.families.find( { "isRegistered" : false })
结果:
{
"_id": ObjectId("58f65e1198f3a12c7090e68c"),
"id": "WakefieldFamily",
"parents": [{
"familyName": "Wakefield",
"givenName": "Robin"
}, {
"familyName": "Miller",
"givenName": "Ben"
}],
"children": [{
"familyName": "Merriam",
"givenName": "Jesse",
"gender": "female",
"grade": 1,
"pets": [{
"givenName": "Goofy"
}, {
"givenName": "Shadow"
}]
}, {
"familyName": "Miller",
"givenName": "Lisa",
"gender": "female",
"grade": 8
}],
"address": {
"state": "NY",
"county": "Manhattan",
"city": "NY"
},
"creationDate": 1431620462,
"isRegistered": false
}
示例查询 5
下一个查询返回所有未注册且所在州为纽约 (NY) 的家庭。
查询:
db.families.find( { "isRegistered" : false, "address.state" : "NY" })
结果:
{
"_id": ObjectId("58f65e1198f3a12c7090e68c"),
"id": "WakefieldFamily",
"parents": [{
"familyName": "Wakefield",
"givenName": "Robin"
}, {
"familyName": "Miller",
"givenName": "Ben"
}],
"children": [{
"familyName": "Merriam",
"givenName": "Jesse",
"gender": "female",
"grade": 1,
"pets": [{
"givenName": "Goofy"
}, {
"givenName": "Shadow"
}]
}, {
"familyName": "Miller",
"givenName": "Lisa",
"gender": "female",
"grade": 8
}],
"address": {
"state": "NY",
"county": "Manhattan",
"city": "NY"
},
"creationDate": 1431620462,
"isRegistered": false
}
示例查询 6
下一个查询返回子女读 8 年级的所有家庭。
查询:
db.families.find( { children : { $elemMatch: { grade : 8 }} } )
结果:
{
"_id": ObjectId("58f65e1198f3a12c7090e68c"),
"id": "WakefieldFamily",
"parents": [{
"familyName": "Wakefield",
"givenName": "Robin"
}, {
"familyName": "Miller",
"givenName": "Ben"
}],
"children": [{
"familyName": "Merriam",
"givenName": "Jesse",
"gender": "female",
"grade": 1,
"pets": [{
"givenName": "Goofy"
}, {
"givenName": "Shadow"
}]
}, {
"familyName": "Miller",
"givenName": "Lisa",
"gender": "female",
"grade": 8
}],
"address": {
"state": "NY",
"county": "Manhattan",
"city": "NY"
},
"creationDate": 1431620462,
"isRegistered": false
}
示例查询 7
下一个查询返回有 3 个子女的家庭。
查询:
db.Family.find( {children: { $size:3} } )
结果:
不返回任何结果,因为没有任何家庭的子女数超过 2 个。 仅当参数值为 2
时此查询才能成功,并返回完整的文档。
后续步骤
在本教程中,已完成以下任务:
- 了解如何使用 Azure Cosmos DB for MongoDB 进行查询
现可继续学习下一教程,了解如何多区域分发数据。