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4. MongoDB文档操作

4.1 插入文档

3.2 版本之后新增了db.collection.insertOne()和db.collection.insertMany()

新增单个文档

  • InsertOne：支持 writeConcern
db.collection.insertOne(
    <document>, 
    { 
        writeConcern: <document> 
    } 
)

writeConcern 决定一个写操作落到多少个节点上才算成功。writeConcern的取值包括：

0: 发起写操作，不关心是否成功；

1一 集群最大数据节点数：写操作需要被复制到指定节点数才算成功；

majority：写操作需要被复制到大多数节点上才算成功。

  • insert: 若插入的数据主键已经存在，则会抛DuplicateKeyException异常，提示主键重复，不保存当前数据。
  • save：如果_id主键存在则更新数据，如果不存在就插入数据。 
cd tmp/mongodb/bin

> use appdb
switched to db appdb

> db.emps.save({x:1})
WriteResult({ "nInserted" : 1 })

> db.emps.save({x:2})
WriteResult({ "nInserted" : 1 })

> db.emps.insert({x:3})
WriteResult({ "nInserted" : 1 })

> db.emps.insertOne({x:3})
{
    "acknowledged" : true,
    "insertedId" : ObjectId("623af68d22bf9364d532766e")
}

> db.emps.find()
{ "_id" : ObjectId("623af5ed22bf9364d532766b"), "x" : 1 }
{ "_id" : ObjectId("623af5f622bf9364d532766c"), "x" : 2 }
{ "_id" : ObjectId("623af62622bf9364d532766d"), "x" : 3 }
{ "_id" : ObjectId("623af68d22bf9364d532766e"), "x" : 3 }

> db.user.insert({"name":"jacob"})
WriteResult({ "nInserted" : 1 })


> db.user.find()
{ "_id" : ObjectId("623af9c722bf9364d532766f"), "name" : "jacob" }

db.user.insert({"name":"jacob", "age":"31"})

> db.user.find()
{ "_id" : ObjectId("623af9c722bf9364d532766f"), "name" : "jacob" }
{ "_id" : ObjectId("623af9ff22bf9364d5327670"), "name" : "jacob", "age" : "31" }

> db.user.insertMany([{"name":"jack", "age":"30"}, {"name":"christine", "age":"28"}])
{
    "acknowledged" : true,
    "insertedIds" : [
        ObjectId("623afa4a22bf9364d5327671"),
        ObjectId("623afa4a22bf9364d5327672")
    ]
}

> db.user.find()
{ "_id" : ObjectId("623af9c722bf9364d532766f"), "name" : "jacob" }
{ "_id" : ObjectId("623af9ff22bf9364d5327670"), "name" : "jacob", "age" : "31" }
{ "_id" : ObjectId("623afa4a22bf9364d5327671"), "name" : "jack", "age" : "30" }
{ "_id" : ObjectId("623afa4a22bf9364d5327672"), "name" : "christine", "age" : "28" }

批量新增文档

  • insertMany：向指定集合中插入多条文档数据 
db.collection.insertMany(
    [ <document 1> <document 2>, ...], 
    {
        writeConcern: <document>, 
        ordered: <boolean>
    }
)
  • writeConcern：写入策略，默认为 1, 即要求确认写操作，0是不要求。
  • ordered：指定是否按顺序写入，默认true，按顺序写入。
  • insert和save也可以实现批量插入 
> db.emps.insert([{x:3},{y:5}])
BulkWriteResult({
    "writeErrors" : [ ],
    "writeConcernErrors" : [ ],
    "nInserted" : 2,
    "nUpserted" : 0,
    "nMatched" : 0,
    "nModified" : 0,
    "nRemoved" : 0,
    "upserted" : [ ]
})

> db.emps.save([{x:3, y:0},{y:5, z:7}])
BulkWriteResult({
    "writeErrors" : [ ],
    "writeConcernErrors" : [ ],
    "nInserted" : 2,
    "nUpserted" : 0,
    "nMatched" : 0,
    "nModified" : 0,
    "nRemoved" : 0,
    "upserted" : [ ]
})

> db.emps.insertMany([{x:3, y:0},{y:5, z:7}])
{
    "acknowledged" : true,
    "insertedIds" : [
        ObjectId("623afead22bf9364d5327678"),
        ObjectId("623afead22bf9364d5327679")
    ]
}

测试：

批量插入50条随机数据 编辑脚本book.js 

var tags = ["nosql","mongodb","document","developer","popular"]; 
var types = ["technology","sociality","travel","novel","literature"]; 
var books=[]; 
for(var i=0;i<50;i++){ 
    var typeIdx = Math.floor(Math.random()*types.length); 
    var tagIdx = Math.floor(Math.random()*tags.length); 
    var favCount = Math.floor(Math.random()-100);
    var book = { 
        title: "book-" +i, 
        type: types[typeIdx], 
        tag: tags[tagIdx], 
        favCount: favCount, 
        author: "xxx"+i 
    };
    books.push(book)
} 
db.books.insertMany(books);

vim book.js

[root@jabox bin]# ./mongo localhost:27017 -u appdb -p jack --authenticationDatabase=appdb
MongoDB shell version v4.4.13
connecting to: mongodb://localhost:27017/test?authSource=appdb&compressors=disabled&gssapiServiceName=mongodb
Implicit session: session { "id" : UUID("71e14edf-9b18-4acd-9a47-8f40178950b9") }
MongoDB server version: 4.4.13
> use appdb
switched to db appdb

> load("book.js")
true

> pwd()
/home/vagrant/tmp/mongodb-linux-x86_64-rhel70-4.4.13/bin


> db.books.find()
{ "_id" : ObjectId("623b0766b815b989a2335e75"), "title" : "book-0", "type" : "novel", "tag" : "document", "favCount" : -100, "author" : "xxx0" }
{ "_id" : ObjectId("623b0766b815b989a2335e76"), "title" : "book-1", "type" : "literature", "tag" : "mongodb", "favCount" : -100, "author" : "xxx1" }
{ "_id" : ObjectId("623b0766b815b989a2335e77"), "title" : "book-2", "type" : "sociality", "tag" : "mongodb", "favCount" : -100, "author" : "xxx2" }
{ "_id" : ObjectId("623b0766b815b989a2335e78"), "title" : "book-3", "type" : "sociality", "tag" : "popular", "favCount" : -100, "author" : "xxx3" }
{ "_id" : ObjectId("623b0766b815b989a2335e79"), "title" : "book-4", "type" : "literature", "tag" : "popular", "favCount" : -100, "author" : "xxx4" }
{ "_id" : ObjectId("623b0766b815b989a2335e7a"), "title" : "book-5", "type" : "technology", "tag" : "popular", "favCount" : -100, "author" : "xxx5" }
{ "_id" : ObjectId("623b0766b815b989a2335e7b"), "title" : "book-6", "type" : "travel", "tag" : "nosql", "favCount" : -100, "author" : "xxx6" }
{ "_id" : ObjectId("623b0766b815b989a2335e7c"), "title" : "book-7", "type" : "travel", "tag" : "mongodb", "favCount" : -100, "author" : "xxx7" }
{ "_id" : ObjectId("623b0766b815b989a2335e7d"), "title" : "book-8", "type" : "sociality", "tag" : "mongodb", "favCount" : -100, "author" : "xxx8" }
{ "_id" : ObjectId("623b0766b815b989a2335e7e"), "title" : "book-9", "type" : "sociality", "tag" : "popular", "favCount" : -100, "author" : "xxx9" }
{ "_id" : ObjectId("623b0766b815b989a2335e7f"), "title" : "book-10", "type" : "travel", "tag" : "nosql", "favCount" : -100, "author" : "xxx10" }
{ "_id" : ObjectId("623b0766b815b989a2335e80"), "title" : "book-11", "type" : "literature", "tag" : "popular", "favCount" : -100, "author" : "xxx11" }
{ "_id" : ObjectId("623b0766b815b989a2335e81"), "title" : "book-12", "type" : "novel", "tag" : "developer", "favCount" : -100, "author" : "xxx12" }
{ "_id" : ObjectId("623b0766b815b989a2335e82"), "title" : "book-13", "type" : "sociality", "tag" : "mongodb", "favCount" : -100, "author" : "xxx13" }
{ "_id" : ObjectId("623b0766b815b989a2335e83"), "title" : "book-14", "type" : "sociality", "tag" : "popular", "favCount" : -100, "author" : "xxx14" }
{ "_id" : ObjectId("623b0766b815b989a2335e84"), "title" : "book-15", "type" : "sociality", "tag" : "developer", "favCount" : -100, "author" : "xxx15" }
{ "_id" : ObjectId("623b0766b815b989a2335e85"), "title" : "book-16", "type" : "travel", "tag" : "developer", "favCount" : -100, "author" : "xxx16" }
{ "_id" : ObjectId("623b0766b815b989a2335e86"), "title" : "book-17", "type" : "travel", "tag" : "developer", "favCount" : -100, "author" : "xxx17" }
{ "_id" : ObjectId("623b0766b815b989a2335e87"), "title" : "book-18", "type" : "sociality", "tag" : "developer", "favCount" : -100, "author" : "xxx18" }
{ "_id" : ObjectId("623b0766b815b989a2335e88"), "title" : "book-19", "type" : "travel", "tag" : "mongodb", "favCount" : -100, "author" : "xxx19" }
Type "it" for more

3.2 查询文档

find 查询集合中的若干文档。语法格式如下： 

db.collection.find(query, projection)

选择语言

  • query：可选, 使用查询操作符指定查询条件
  • projection: 可选，使用投影操作符指定返回的键。 查询时返回文档中所有键值，只需省略该参数即可（默认省略）。投影时，Id为1的时候， 其他字段必须为1; Id是0的时候，其他字段可以是0；如果没有_id字段约束，多个同为0或同。 
> show tables
books
emps
user

> db.books.find()
{ "_id" : ObjectId("623b0766b815b989a2335e75"), "title" : "book-0", "type" : "novel", "tag" : "document", "favCount" : -100, "author" : "xxx0" }
{ "_id" : ObjectId("623b0766b815b989a2335e76"), "title" : "book-1", "type" : "literature", "tag" : "mongodb", "favCount" : -100, "author" : "xxx1" }
...

如果查询返回的条目数量较多，mongo shell则会自动实现分批显示。默认倩况下每次只显示20。条，可以输入it命令读取下一批。 findOne查询集合中的第一个文档。语法格式如下： 

> it
{ "_id" : ObjectId("623b0766b815b989a2335e9d"), "title" : "book-40", "type" : "technology", "tag" : "developer", "favCount" : -100, "author" : "xxx40" }
{ "_id" : ObjectId("623b0766b815b989a2335e9e"), "title" : "book-41", "type" : "novel", "tag" : "developer", "favCount" : -100, "author" : "xxx41" }
{ "_id" : ObjectId("623b0766b815b989a2335e9f"), "title" : "book-42", "type" : "novel", "tag" : "nosql", "favCount" : -100, "author" : "xxx42" }
{ "_id" : ObjectId("623b0766b815b989a2335ea0"), "title" : "book-43", "type" : "novel", "tag" : "document", "favCount" : -100, "author" : "xxx43" }
...

> db.books.find({title:"book-20"})
{ "_id" : ObjectId("623b0766b815b989a2335e89"), "title" : "book-20", "type" : "sociality", "tag" : "document", "favCount" : -100, "author" : "xxx20" }

> db.books.find({type:"travel", tag:"developer"})
{ "_id" : ObjectId("623b0766b815b989a2335e85"), "title" : "book-16", "type" : "travel", "tag" : "developer", "favCount" : -100, "author" : "xxx16" }
{ "_id" : ObjectId("623b0766b815b989a2335e86"), "title" : "book-17", "type" : "travel", "tag" : "developer", "favCount" : -100, "author" : "xxx17" }
{ "_id" : ObjectId("623b0766b815b989a2335e92"), "title" : "book-29", "type" : "travel", "tag" : "developer", "favCount" : -100, "author" : "xxx29" }

> db.books.find({type:"travel", tag:"developer"},{title:1,favCount:1})

{ "_id" : ObjectId("623b0766b815b989a2335e85"), "title" : "book-16", "favCount" : -100 }
{ "_id" : ObjectId("623b0766b815b989a2335e86"), "title" : "book-17", "favCount" : -100 }
{ "_id" : ObjectId("623b0766b815b989a2335e92"), "title" : "book-29", "favCount" : -100 }

> db.books.findOne({type:"travel", tag:"developer"},{title:1,favCount:1})
{
    "_id" : ObjectId("623b0766b815b989a2335e85"),
    "title" : "book-16",
    "favCount" : -100
}

条件查询

指定条件查询

＃查询带有nosql标签的book文档
db.books.find({tag:"nosql"})


> db.books.find({tag:"nosql"})
{ "_id" : ObjectId("623b0766b815b989a2335e7b"), "title" : "book-6", "type" : "travel", "tag" : "nosql", "favCount" : -100, "author" : "xxx6" }
{ "_id" : ObjectId("623b0766b815b989a2335e7f"), "title" : "book-10", "type" : "travel", "tag" : "nosql", "favCount" : -100, "author" : "xxx10" }
{ "_id" : ObjectId("623b0766b815b989a2335e8c"), "title" : "book-23", "type" : "sociality", "tag" : "nosql", "favCount" : -100, "author" : "xxx23" }
{ "_id" : ObjectId("623b0766b815b989a2335e8f"), "title" : "book-26", "type" : "literature", "tag" : "nosql", "favCount" : -100, "author" : "xxx26" }
{ "_id" : ObjectId("623b0766b815b989a2335e94"), "title" : "book-31", "type" : "technology", "tag" : "nosql", "favCount" : -100, "author" : "xxx31" }
{ "_id" : ObjectId("623b0766b815b989a2335e99"), "title" : "book-36", "type" : "travel", "tag" : "nosql", "favCount" : -100, "author" : "xxx36" }
{ "_id" : ObjectId("623b0766b815b989a2335e9f"), "title" : "book-42", "type" : "novel", "tag" : "nosql", "favCount" : -100, "author" : "xxx42" }
{ "_id" : ObjectId("623b0766b815b989a2335ea2"), "title" : "book-45", "type" : "travel", "tag" : "nosql", "favCount" : -100, "author" : "xxx45" }
{ "_id" : ObjectId("623b0766b815b989a2335ea5"), "title" : "book-48", "type" : "literature", "tag" : "nosql", "favCount" : -100, "author" : "xxx48" }
{ "_id" : ObjectId("623b0766b815b989a2335ea6"), "title" : "book-49", "type" : "sociality", "tag" : "nosql", "favCount" : -100, "author" : "xxx49" }

按照Id查询单个book文档： 

> db.books.find({_id:ObjectId("623b0766b815b989a2335e8f")})
{ "_id" : ObjectId("623b0766b815b989a2335e8f"), "title" : "book-26", "type" : "literature", "tag" : "nosql", "favCount" : -100, "author" : "xxx26" }

＃汽询分类为"travel"、收藏数超过60个的book之档： 

db.books.find({type:"travel",favCount:{$gt:60}})

查询条件对照表

Alt Image Text

Alt Image Text

查询逻辑对照表

Alt Image Text

db.books.find({tag:{$in:["nosql","document"]}}) 

> db.books.find({tag:{$in:["nosql","document"]}})
{ "_id" : ObjectId("623b0766b815b989a2335e75"), "title" : "book-0", "type" : "novel", "tag" : "document", "favCount" : -100, "author" : "xxx0" }
{ "_id" : ObjectId("623b0766b815b989a2335e7b"), "title" : "book-6", "type" : "travel", "tag" : "nosql", "favCount" : -100, "author" : "xxx6" }
{ "_id" : ObjectId("623b0766b815b989a2335e7f"), "title" : "book-10", "type" : "travel", "tag" : "nosql", "favCount" : -100, "author" : "xxx10" }
{ "_id" : ObjectId("623b0766b815b989a2335e89"), "title" : "book-20", "type" : "sociality", "tag" : "document", "favCount" : -100, "author" : "xxx20" }
{ "_id" : ObjectId("623b0766b815b989a2335e8c"), "title" : "book-23", "type" : "sociality", "tag" : "nosql", "favCount" : -100, "author" : "xxx23" }
{ "_id" : ObjectId("623b0766b815b989a2335e8f"), "title" : "book-26", "type" : "literature", "tag" : "nosql", "favCount" : -100, "author" : "xxx26" }
{ "_id" : ObjectId("623b0766b815b989a2335e90"), "title" : "book-27", "type" : "technology", "tag" : "document", "favCount" : -100, "author" : "xxx27" }
{ "_id" : ObjectId("623b0766b815b989a2335e93"), "title" : "book-30", "type" : "travel", "tag" : "document", "favCount" : -100, "author" : "xxx30" }
...

查询逻辑运算符.

  • $It：存在并小于
  • $Ite:存在并小于等于
  • $gt: 存在并大于
  • $gte: 存在并大于等于
  • $ne: 不存在或存在但不等于
  • $in：存在并在指定数组中
  • $nin:不存在或不在指定数组中
  • $or：匹配两个或多个条件中的一个
  • $and:匹配全部条件 
> db.books.find({$and:[{tag:"nosql"}, {favCount:{$gte:-100}}]})
{ "_id" : ObjectId("623b0766b815b989a2335e7b"), "title" : "book-6", "type" : "travel", "tag" : "nosql", "favCount" : -100, "author" : "xxx6" }
{ "_id" : ObjectId("623b0766b815b989a2335e7f"), "title" : "book-10", "type" : "travel", "tag" : "nosql", "favCount" : -100, "author" : "xxx10" }
{ "_id" : ObjectId("623b0766b815b989a2335e8c"), "title" : "book-23", "type" : "sociality", "tag" : "nosql", "favCount" : -100, "author" : "xxx23" }
{ "_id" : ObjectId("623b0766b815b989a2335e8f"), "title" : "book-26", "type" : "literature", "tag" : "nosql", "favCount" : -100, "author" : "xxx26" }
{ "_id" : ObjectId("623b0766b815b989a2335e94"), "title" : "book-31", "type" : "technology", "tag" : "nosql", "favCount" : -100, "author" : "xxx31" }
{ "_id" : ObjectId("623b0766b815b989a2335e99"), "title" : "book-36", "type" : "travel", "tag" : "nosql", "favCount" : -100, "author" : "xxx36" }
{ "_id" : ObjectId("623b0766b815b989a2335e9f"), "title" : "book-42", "type" : "novel", "tag" : "nosql", "favCount" : -100, "author" : "xxx42" }
{ "_id" : ObjectId("623b0766b815b989a2335ea2"), "title" : "book-45", "type" : "travel", "tag" : "nosql", "favCount" : -100, "author" : "xxx45" }
{ "_id" : ObjectId("623b0766b815b989a2335ea5"), "title" : "book-48", "type" : "literature", "tag" : "nosql", "favCount" : -100, "author" : "xxx48" }
{ "_id" : ObjectId("623b0766b815b989a2335ea6"), "title" : "book-49", "type" : "sociality", "tag" : "nosql", "favCount" : -100, "author" : "xxx49" }

排序＆分页

指定排序:

在MongoDB中使用sort()方法对数据进行排序

＃指定按收藏数(favcount）降序返回 
db.books.find({type:"travel"}).sort({favCount:-1})

分页查询

skip用于指定跳过记录数，limit 则用于限定返回结果数量。可以在执行find命令的同时指定skip,limit参数，一次实现分页的功能。比如，假定每页大小为8条， 查询第3页的book文档：

> db.books.find().skip(8).limit(4)
{ "_id" : ObjectId("623b0766b815b989a2335e7d"), "title" : "book-8", "type" : "sociality", "tag" : "mongodb", "favCount" : -100, "author" : "xxx8" }
{ "_id" : ObjectId("623b0766b815b989a2335e7e"), "title" : "book-9", "type" : "sociality", "tag" : "popular", "favCount" : -100, "author" : "xxx9" }
{ "_id" : ObjectId("623b0766b815b989a2335e7f"), "title" : "book-10", "type" : "travel", "tag" : "nosql", "favCount" : -100, "author" : "xxx10" }
{ "_id" : ObjectId("623b0766b815b989a2335e80"), "title" : "book-11", "type" : "literature", "tag" : "popular", "favCount" : -100, "author" : "xxx11" }

> db.books.find({tag:{$in:["nosql","document"]}}).sort({favCount:-1})
{ "_id" : ObjectId("623b0766b815b989a2335e75"), "title" : "book-0", "type" : "novel", "tag" : "document", "favCount" : -100, "author" : "xxx0" }
{ "_id" : ObjectId("623b0766b815b989a2335e7b"), "title" : "book-6", "type" : "travel", "tag" : "nosql", "favCount" : -100, "author" : "xxx6" }
{ "_id" : ObjectId("623b0766b815b989a2335e7f"), "title" : "book-10", "type" : "travel", "tag" : "nosql", "favCount" : -100, "author" : "xxx10" }
{ "_id" : ObjectId("623b0766b815b989a2335e89"), "title" : "book-20", "type" : "sociality", "tag" : "document", "favCount" : -100, "author" : "xxx20" }
{ "_id" : ObjectId("623b0766b815b989a2335e8c"), "title" : "book-23", "type" : "sociality", "tag" : "nosql", "favCount" : -100, "author" : "xxx23" }
...

正则表达式匹配查询

MongoDB使用$regex操作符来设置匹配字符串的正则表达式。

//使用止则表达式查找type包含so 字符串的 books
db.books.find({type:{$regex:"so"}}) 

> db.books.find({type:{$regex:"so"}})
{ "_id" : ObjectId("623b0766b815b989a2335e77"), "title" : "book-2", "type" : "sociality", "tag" : "mongodb", "favCount" : -100, "author" : "xxx2" }
{ "_id" : ObjectId("623b0766b815b989a2335e78"), "title" : "book-3", "type" : "sociality", "tag" : "popular", "favCount" : -100, "author" : "xxx3" }



/／或者 
db.books.find({type:/so/}) 

db.books.find({type:/so/})
{ "_id" : ObjectId("623b0766b815b989a2335e77"), "title" : "book-2", "type" : "sociality", "tag" : "mongodb", "favCount" : -100, "author" : "xxx2" }
{ "_id" : ObjectId("623b0766b815b989a2335e78"), "title" : "book-3", "type" : "sociality", "tag" : "popular", "favCount" : -100, "author" : "xxx3" }
{ "_id" : ObjectId("623b0766b815b989a2335e7d"), "title" : "book-8", "type" : "sociality", "tag" : "mongodb", "favCount" : -100, "author" : "xxx8" }

3.3 更新文档

可以用update命令对指定的数据进行更新，命令的格式如下： 

db.collection.update(query,update,options)
  • query： 描述更新的查询条件；
  • update: 描述更新的动作及新的内容
  • options：描述更新的选项
    • upsert：可选，如果不存在update的记录，是否插入新的i己录。默认false，不插入
    • multi: 可选，是否按条件查询出的多条记录全部更新。默认false，只更新找到的第一条记录
    • writeConcern：可选，决定一个写操作落到多少个节点上才算成功。

更新操作符

Alt Image Text

更新单个文档

某个book文档被收藏了，则需要将该文档的favCount 字段自增

> show dbs
appdb  0.000GB
> use appdb
switched to db appdb
> show tables
books
emps
user

db.books.update({_id: ObjectId("623b0766b815b989a2335e84")},{$inc:{favCount: 160}})

db.books.update({_id: ObjectId("623b0766b815b989a2335e84")},{$inc:{favCount: 160}})
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })

更新多个文档

默认情况下，update命令只在更新第一个文档之后返回，如果需要更新多个文档，则可以使用multi选项。

将分类为"novel"的文档的增加发布时间（publishedDate)

db.books.update({tag: "novel"},{$set:{publishDate: new Date()}}, {"multi": true})

> db.books.find({tag: "nosql"})
{ "_id" : ObjectId("623b0766b815b989a2335e7b"), "title" : "book-6", "type" : "travel", "tag" : "nosql", "favCount" : -100, "author" : "xxx6" }
{ "_id" : ObjectId("623b0766b815b989a2335e7f"), "title" : "book-10", "type" : "travel", "tag" : "nosql", "favCount" : -100, "author" : "xxx10" }
{ "_id" : ObjectId("623b0766b815b989a2335e8c"), "title" : "book-23", "type" : "sociality", "tag" : "nosql", "favCount" : -100, "author" : "xxx23" }
{ "_id" : ObjectId("623b0766b815b989a2335e8f"), "title" : "book-26", "type" : "literature", "tag" : "nosql", "favCount" : -100, "author" : "xxx26" }
{ "_id" : ObjectId("623b0766b815b989a2335e94"), "title" : "book-31", "type" : "technology", "tag" : "nosql", "favCount" : -100, "author" : "xxx31" }
{ "_id" : ObjectId("623b0766b815b989a2335e99"), "title" : "book-36", "type" : "travel", "tag" : "nosql", "favCount" : -100, "author" : "xxx36" }
{ "_id" : ObjectId("623b0766b815b989a2335e9f"), "title" : "book-42", "type" : "novel", "tag" : "nosql", "favCount" : -100, "author" : "xxx42" }
{ "_id" : ObjectId("623b0766b815b989a2335ea2"), "title" : "book-45", "type" : "travel", "tag" : "nosql", "favCount" : -100, "author" : "xxx45" }
{ "_id" : ObjectId("623b0766b815b989a2335ea5"), "title" : "book-48", "type" : "literature", "tag" : "nosql", "favCount" : -100, "author" : "xxx48" }
{ "_id" : ObjectId("623b0766b815b989a2335ea6"), "title" : "book-49", "type" : "sociality", "tag" : "nosql", "favCount" : -100, "author" : "xxx49" }

db.books.update({tag: "nosql"},{$set:{publishDate: new Date()}})

db.books.update({tag: "nosql"},{$set:{publishDate: new Date()}})
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })

> db.books.update({tag: "nosql"},{$set:{publishDate: new Date()}}, {"multi": true})
WriteResult({ "nMatched" : 10, "nUpserted" : 0, "nModified" : 10 })

multi:可选，mongodb默认是false，只更新找到的第一条记录，如果这个参数为true，就把按条件查出来多条记录全部更新 

> db.books.find({tag: "nosql"})
{ "_id" : ObjectId("623b0766b815b989a2335e7b"), "title" : "book-6", "type" : "travel", "tag" : "nosql", "favCount" : -100, "author" : "xxx6", "publishDate" : ISODate("2022-03-26T09:09:54.851Z") }
{ "_id" : ObjectId("623b0766b815b989a2335e7f"), "title" : "book-10", "type" : "travel", "tag" : "nosql", "favCount" : -100, "author" : "xxx10", "publishDate" : ISODate("2022-03-26T09:09:54.851Z") }
{ "_id" : ObjectId("623b0766b815b989a2335e8c"), "title" : "book-23", "type" : "sociality", "tag" : "nosql", "favCount" : -100, "author" : "xxx23", "publishDate" : ISODate("2022-03-26T09:09:54.851Z") }
{ "_id" : ObjectId("623b0766b815b989a2335e8f"), "title" : "book-26", "type" : "literature", "tag" : "nosql", "favCount" : -100, "author" : "xxx26", "publishDate" : ISODate("2022-03-26T09:09:54.851Z") }
{ "_id" : ObjectId("623b0766b815b989a2335e94"), "title" : "book-31", "type" : "technology", "tag" : "nosql", "favCount" : -100, "author" : "xxx31", "publishDate" : ISODate("2022-03-26T09:09:54.851Z") }
{ "_id" : ObjectId("623b0766b815b989a2335e99"), "title" : "book-36", "type" : "travel", "tag" : "nosql", "favCount" : -100, "author" : "xxx36", "publishDate" : ISODate("2022-03-26T09:09:54.851Z") }
{ "_id" : ObjectId("623b0766b815b989a2335e9f"), "title" : "book-42", "type" : "novel", "tag" : "nosql", "favCount" : -100, "author" : "xxx42", "publishDate" : ISODate("2022-03-26T09:09:54.851Z") }
{ "_id" : ObjectId("623b0766b815b989a2335ea2"), "title" : "book-45", "type" : "travel", "tag" : "nosql", "favCount" : -100, "author" : "xxx45", "publishDate" : ISODate("2022-03-26T09:09:54.851Z") }
{ "_id" : ObjectId("623b0766b815b989a2335ea5"), "title" : "book-48", "type" : "literature", "tag" : "nosql", "favCount" : -100, "author" : "xxx48", "publishDate" : ISODate("2022-03-26T09:09:54.851Z") }
{ "_id" : ObjectId("623b0766b815b989a2335ea6"), "title" : "book-49", "type" : "sociality", "tag" : "nosql", "favCount" : -100, "author" : "xxx49", "publishDate" : ISODate("2022-03-26T09:09:54.851Z") }

update命令的选项配置较多，为了简化使用还可以使用一些快捷命令：

  • updateOne:更新单个文档。
  • updateMany：更新多个文档。
  • replaceOne：替换单个文档。 
> db.books.updateMany({type: "novel"},{$set:{publishDate: new Date()}})

> db.books.updateMany({type: "novel"},{$set:{publishDate: new Date()}})
{ "acknowledged" : true, "matchedCount" : 9, "modifiedCount" : 9 }

> db.books.find({type: "novel"})
{ "_id" : ObjectId("623b0766b815b989a2335e75"), "title" : "book-0", "type" : "novel", "tag" : "document", "favCount" : -100, "author" : "xxx0", "publishDate" : ISODate("2022-03-26T09:17:39.729Z") }
{ "_id" : ObjectId("623b0766b815b989a2335e81"), "title" : "book-12", "type" : "novel", "tag" : "developer", "favCount" : -100, "author" : "xxx12", "publishDate" : ISODate("2022-03-26T09:17:39.729Z") }
{ "_id" : ObjectId("623b0766b815b989a2335e8b"), "title" : "book-22", "type" : "novel", "tag" : "mongodb", "favCount" : -100, "author" : "xxx22", "publishDate" : ISODate("2022-03-26T09:17:39.729Z") }
{ "_id" : ObjectId("623b0766b815b989a2335e96"), "title" : "book-33", "type" : "novel", "tag" : "popular", "favCount" : -100, "author" : "xxx33", "publishDate" : ISODate("2022-03-26T09:17:39.729Z") }

使用upsert命令

Upsert是一种特殊的更新，其表现为如果目标文档不存在，则执行插入命令。 

db.books.update( 
    {title:"my book"},
    {$set:{tags:["nosql","mongodb"] ,type:"none", author:"jacob"}},
    {upsert:true}
)

> db.books.update(
... {title:"my book"},
... {$set:{tags:["nosql","mongodb"] ,type:"none", author:"jacob"}},
... {upsert:true}
... )
WriteResult({
    "nMatched" : 0,
    "nUpserted" : 1,
    "nModified" : 0,
    "_id" : ObjectId("623edc883d8c8e61e23b57c3")
})

nMatched, nModified都为0，表示没有文档被匹配及更新，nUpserted=1提示执行了Upsert动作 

> db.books.find({title: "my book"})
{ "_id" : ObjectId("623edc883d8c8e61e23b57c3"), "title" : "my book", "author" : "jacob", "tags" : [ "nosql", "mongodb" ], "type" : "none" }

实现replace语义

update命令中的更新描述（update)通常由操作符描述，如果更新描述中不包含任何操作符，那么MongoDB会实现文档的replace语义 

db.books.update( 
    {title:"my book"}, 
    {justTitle:"my first book"} 
)

> db.books.update(
... {title:"my book"},
... {justTitle:"my first book"}
... )
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })

> db.books.find({justTitle:"my first book"})
{ "_id" : ObjectId("623edc883d8c8e61e23b57c3"), "justTitle" : "my first book" }

findAndModify命令

findAndModify兼容了查询和修改指定文档的功能，findAndModify只能更新单个文档 

//将某个book文档的收藏数（favCount)加1
db.books.findAndModify({
    query: {_id: ObjectId("623b0766b815b989a2335e75")},
    update: {$inc:{favCount: 130}}
})

> db.books.findAndModify({
... query: {_id: ObjectId("623b0766b815b989a2335e75")},
... update: {$inc:{favCount: 130}}
... })
{
    "_id" : ObjectId("623b0766b815b989a2335e75"),
    "title" : "book-0",
    "type" : "novel",
    "tag" : "document",
    "favCount" : -100,
    "author" : "xxx0",
    "publishDate" : ISODate("2022-03-26T09:17:39.729Z")
}

该操作会返回符合查询条件的文档数据，并完成对文档的修改。 

db.books.find({"_id": ObjectId("623b0766b815b989a2335e75")})

> db.books.find({"_id": ObjectId("623b0766b815b989a2335e75")})
{ "_id" : ObjectId("623b0766b815b989a2335e75"), "title" : "book-0", "type" : "novel", "tag" : "document", "favCount" : 30, "author" : "xxx0", "publishDate" : ISODate("2022-03-26T09:17:39.729Z") }

"favCount" : 30, "author" : "xxx0", "publishDate" :

默认情况下，findAndModify会返回修改前的“旧“数据。如果希望返回修改改后的数据，则可以指定new选项

new: true

db.books.findAndModify({
    query: {_id: ObjectId("623b0766b815b989a2335e75")},
    update: {$inc:{favCount: 130}},
    new: true
})

> db.books.findAndModify({
... query: {_id: ObjectId("623b0766b815b989a2335e75")},
... update: {$inc:{favCount: 130}},
... new: true
... })
{
    "_id" : ObjectId("623b0766b815b989a2335e75"),
    "title" : "book-0",
    "type" : "novel",
    "tag" : "document",
    "favCount" : 160,
    "author" : "xxx0",
    "publishDate" : ISODate("2022-03-26T09:17:39.729Z")
}

与findAndModify语义相近的命令如下

  • findOneAndUpdate:更新单个文档并返回更新前（或更新后）的文档。
  • findOneAndReplace:替换单个文档并返回替换前（或替换后）的文档。

3.4 删除文档

使用remove删除文档

  • remove命令需要配合查询条件使用
  • 匹配查询条件的文档会被删除；
  • 指定一个空文档条件会删除所有文档

示例 

db.user.remove({age:28}) // 删除age等于28 的记录 
db.user.remove({age:{$lt:25}}) // 删除age小于 25的记录 
db.user.remove({}) // 删除所有记录
db.user.remove() //报错

remove命令会删除匹配条件的全部文档，如果希望明确限定只删除一个文档，则需要指justOne参数，命令格式如下 

db.collection.remove(query,justOne)

例如：删除满足type:novel条件的首条记录 

db.books.remove({type:"novel"},true) 

> db.books.remove({type:"novel"},true)
WriteResult({ "nRemoved" : 1 })

> db.books.remove()
uncaught exception: Error: remove needs a query :
DBCollection.prototype._parseRemove@src/mongo/shell/collection.js:362:15
DBCollection.prototype.remove@src/mongo/shell/collection.js:389:18
@(shell):1:1

使用delete删除文档

官方推荐使用deleteOne(）和deleteMany(）方法删除文档，语法格式如下：

db.books.deleteMany({})      // 删除集合下全部状态
db.books.deleteMany({type:"novel"})  // 删除type等于novel的全部文档 
db.books.deleteOne({type:"novel"})  /／删除type等于novel的一个文档

注意：

remove, deleteMany等命令需要对查询范围内的文档逐个删除，如果希望删除整个集合，则使用drop命令会更加高效

db.books.deleteOne({type:"travel"}) 

> db.books.deleteOne({type:"travel"})
{ "acknowledged" : true, "deletedCount" : 1 }

返回被删除文档

remove,deleteOne等命令在删除文档后只刽区回确认性的信息，如果希望获得被删除的文档，则可以使用findOneAndDelete命令 

db.books.findOneAndDelete({type:"novel"}) 

> db.books.findOneAndDelete({type:"novel"})
{
    "_id" : ObjectId("623b0766b815b989a2335e81"),
    "title" : "book-12",
    "type" : "novel",
    "tag" : "developer",
    "favCount" : -100,
    "author" : "xxx12",
    "publishDate" : ISODate("2022-03-26T09:17:39.729Z")
}

除了在结果中返回删除文档，findOneAndDelete命令还允许定义"删除的顺序"，即按照指定顺序删除找到的第一个文档

db.books.findOneAndDelete({type:"novel"},{sort:{favCount:1}})

remove, deleteOne等命令只能按默认顺序删除，利用这个特性， findOneAndDelete可以实现队列的先进先出。