一、插入\创建文档

--当插入一个不存在的文档时，会自己主动创建一个文档

[root@racdb ~]# mongo

MongoDB shell version: 2.4.14

connecting to: test

> show collections

> db.cols.insert({bar:"baz"})

> db.cols.find()

{ "_id" :ObjectId("56aac1df4e61b6d9f84d17e0"), "bar" :"baz" }

二、删除文档

--删除全部文档

> db.cols.remove()

--删除符合条件的文档

> db.cols.remove({bar:"baz"})

注意：db.cols.remove()不会删除cols集合本身，原有索引也会保留

三、更新文档

文档替换

--假设把以下文档

>db.users.findOne({"name":"licz"})

{

       "_id" : ObjectId("56a8828b308203e00e436b01"),

       "name" : "licz",

       "friends" : 43,

       "enemies" : 5

}

--更新成以下文档

{

       "_id" : ObjectId("56a8828b308203e00e436b01"),

       "relationships" : {

                "friends" : 43,

                "enemies" : 5

       },

       "username" : "licz"

}

更新方法：

> licz.relationships ={"friends":licz.friends,"enemies":licz.enemies}

{ "friends" : 43,"enemies" : 5 }

> licz.username = licz.name

licz

> delete licz.friends

true

> delete licz.enemies

true

> delete licz.name

true

>db.users.findOne({"name":"licz"})

{

       "_id" : ObjectId("56a8828b308203e00e436b01"),

       "name" : "licz",

       "friends" : 43,

       "enemies" : 5

}

>db.users.update({name:"licz"},licz)

>db.users.findOne({"username":"licz"})

{

       "_id" : ObjectId("56a8828b308203e00e436b01"),

       "relationships" : {

                "friends" : 43,

                "enemies" : 5

       },

       "username" : "licz"

}

使用改动器

1. $set

$set用来改动指定键的值，假设键不存在，就创建它。

>db.users.findOne({"name":"haley"})

{

       "_id" : ObjectId("4b253b067525f35f94b60a31"),

       "name" : "haley",

       "age" : 30,

       "sex" : "male"

}

--增加文档的键值对

> db.users.update({"name":"haley"},{"$set":{"location":"china"}})

> db.users.update({"name":"haley"},{"$set":{"favoritebook":"war and peace"}})

>db.users.findOne({"name":"haley"})

{

       "_id" : ObjectId("4b253b067525f35f94b60a31"),

       "name" : "haley",

       "age" : 30,

       "sex" : "male",

       "location" : "china",

       "favorite book" : "war and peace"

}

--改动"favoritebook"键的值

> db.users.update({"name":"haley"},{"$set":{"favoritebook":"green eggs and ham"}})

>db.users.findOne({"name":"haley"})

{

       "_id" : ObjectId("4b253b067525f35f94b60a31"),

       "name" : "haley",

       "age" : 30,

       "sex" : "male",

       "location" : "china",

       "favorite book" : "green eggs and ham"

}

2. $inc

$inc用来增加/降低文档中键的值，相同假设键不存在，就创建它

>db.analytics.findOne({"url":"www.example.com"})

{

       "_id" : ObjectId("4b253b067525f35f94b60a31"),

       "url" : "www.example.com",

       "pageviews" : 54

}

>db.analytics.update({"url":"www.example.com"},{"$inc":{"pageviews":1}})

>db.analytics.findOne({"url":"www.example.com"})

{

       "_id" : ObjectId("4b253b067525f35f94b60a31"),

       "url" : "www.example.com",

       "pageviews" : 55

}

--增加"visits"键值对

>db.analytics.update({"url":"www.example.com"},{"$inc":{"visits":3}})

>db.analytics.findOne({"url":"www.example.com"})

{

       "_id" : ObjectId("4b253b067525f35f94b60a31"),

       "url" : "www.example.com",

       "pageviews" : 55,

       "visits" : 3

}

注意：能够看$set和$inc改动器的差别：

$set是改动字符型的键值，$inc是改动数值型的键值；都是在不存在键时会自己主动增加上。

数据组改动器

3. $push

$push作用：假设指定的键存在，$push会向已有数组末尾增加一个元素，要是没有就会创建一个新的数据。

>db.blog.posts.findOne({"title":"A Oracle error summary"})

{

        "_id" :ObjectId("56aad2744e61b6d9f84d17e1"),

       "title" : "A Oracle error summary",

       "content" : "..."

}

> db.blog.posts.update({"title":"AOracle error summary"},

...{"$push":{"comments":{"name":"licz","email":"licz@163.com","content":"goodpost!"}}})

>db.blog.posts.findOne({"title":"A Oracle error summary"})

{

       "_id" : ObjectId("56aad2744e61b6d9f84d17e1"),

       "title" : "A Oracle error summary",

       "content" :"...",

       "comments" : [

                {

                        "name" :"licz",

                        "email" :"licz@163.com",

                        "content" :"good post!"

                }

       ]

}

--再次加一个数据元素

... {"$push":{"comments":{"name":"haley","email":"haley@qq.com","content":"thankyou post"}}})

>db.blog.posts.findOne({"title":"A Oracle error summary"})

{

       "_id" : ObjectId("56aad2744e61b6d9f84d17e1"),

       "title" : "A Oracle error summary",

       "content" : "...",

       "comments" : [

                {

                        "name" :"licz",

                        "email" :"licz@163.com",

                        "content" :"good post!"

                },

                {

                        "name" :"haley",

                        "email" :"haley@qq.com",

                        "content" :"thank you post"

                }

       ]

}

4. $ne

$ne能够对键做一些推断，如：使用$ne和$push组，假设一个值不在数组里面就把他加进去，避免插入反复值

> db.papers.findOne()

{

       "_id" : ObjectId("56aadaaa4e61b6d9f84d17e2"),

       "title" : "People life",

       "content" : "..."

}

>db.papers.update({"authorscited":{"$ne":"Richie"}},

...{"$push":{"authorscited":"Richie"}})

> db.papers.findOne()

{

       "_id" : ObjectId("56aadaaa4e61b6d9f84d17e2"),

       "title" : "People life",

       "content" : "...",

       "authors cited" : [

                "Richie"

       ]

}

--再次增加相同元素，文档没有变化

> db.papers.update({"authorscited":{"$ne":"Richie"}},

...{"$push":{"authorscited":"Richie"}})

> db.papers.findOne()

{

       "_id" : ObjectId("56aadaaa4e61b6d9f84d17e2"),

       "title" : "People life",

       "content" : "...",

       "authors cited" : [

                "Richie"

       ]

}

5. $addToSet

$addToSet作用：能够取代$ne和$push组全，在数组里增加一个元素且能增加多个元素，也能避免插入反复值

>db.users.findOne({"username":"licz"}

{

       "_id" : ObjectId("56a8828b308203e00e436b01"),

       "relationships" : {

                "friends" : 43,

                "enemies" : 5

       },

        "username" : "licz"

}

> db.users.update({"username":"licz"},{"$addToSet":{"email":"licz@163.com"}})

>db.users.findOne({"username":"licz"})

{

       "_id" : ObjectId("56a8828b308203e00e436b01"),

       "relationships" : {

                "friends" : 43,

                "enemies" : 5

       },

       "username" : "licz",

       "email" : [

                "licz@163.com"

       ]

}

--再运行增加数组元素

> db.users.update({"username":"licz"},{"$addToSet":{"email":"licz@qq.com"}})

> db.users.findOne({"username":"licz"})

{

       "_id" : ObjectId("56a8828b308203e00e436b01"),

       "relationships" : {

                "friends" : 43,

                "enemies" : 5

       },

       "username" : "licz",

       "email" : [

                "licz@163.com",

               "licz@qq.com"

       ]

}

6. $each

$addToSet和$each组合，能够为数组增加多个不同的值

> db.users.update({"username":"licz"},

...{"$addToSet":{"email":{"$each":["licz@umessage.com","licz@sina.com"]}}})

>db.users.findOne({"username":"licz"})

{

       "_id" : ObjectId("56a8828b308203e00e436b01"),

       "relationships" : {

                "friends" : 43,

                "enemies" : 5

       },

       "username" : "licz",

       "email" : [

                "licz@163.com",

                "licz@qq.com",

                "licz@umessage.com",

                "licz@sina.com"

       ]

}

7. $pop

$pop改动器能够从数组不论什么一端删除元素。

{$pop:{key:1}}从末尾端删除元素

{$pop:{key:-1}}从开头端删除元素

8. $pull

$pull能够基于特定条件来删除数组元素，而不仅仅是根据位置

>db.lists.insert({"todo":["dishs","laundry","drycleaning"]})

> db.lists.update({},{"$pull":{"todo":"laundry"}})

> db.lists.findOne()

{

       "_id" : ObjectId("56aafd4a4e61b6d9f84d17e3"),

       "todo" : [

                "dishs",

                "dry cleaning"

       ]

}

$pull会将全部匹配的部分删掉。对数组[1,1,2,1]运行pull 1,得到的结果是仅仅有一个元素[2]

数组的定位改动器

有两种方法操作数组中的值：通过位置和定位操作符$

数组都是以0开头的，能够直接用下标直接作为键来选择元素。例如以下

>db.blog.posts.findOne({"title" : "A blog post"})

{

       "_id" : ObjectId("4b2d75476cc613d5ee930164"),

       "title" : "A blog post",

       "content" : "...",

       "comments" : [

                {

                        "name" :"joe",

                        "email" :"joe@example.com",

                        "content" :"nice post."

                },

                {

                        "name" :"bob",

                        "email" :"bob@example.com",

                        "content" :"good post."

                }

       ]

}

>db.blog.posts.update({"title" : "A blogpost"},{"$inc":{"comments.0.visits" : 1}})

>db.blog.posts.findOne({"title" : "A blog post"})

{

       "_id" : ObjectId("4b2d75476cc613d5ee930164"),

       "title" : "A blog post",

       "content" : "...",

       "comments" : [

                {

                        "name" :"joe",

                        "email" :"joe@example.com",

                        "content" :"nice post.",

                        "visits" : 1

                },

                {

                        "name" :"bob",

                        "email" :"bob@example.com",

                        "content" : "goodpost."

                }

       ]

}

但非常多情况我们不知道要改动数组下标是多少，这时就能够使用定位操作符$,用来定位查询文档已经匹配的元素，并进行更新。

>db.blog.posts.update({"comments.name":"bob"},{"$set":{"comments.$.name":"licz"}})

>db.blog.posts.findOne({"title" : "A blog post"})

{

       "_id" : ObjectId("4b2d75476cc613d5ee930164"),

       "title" : "A blog post",

       "content" : "...",

       "comments" : [

                {

                        "name" :"joe",

                        "email" :"joe@example.com",

                        "content" :"nice post.",

                        "visits" : 1

                },

                {

                        "name" :"licz",

                        "email" :"bob@example.com",

                        "content" :"good post."

                }

       ]

}

upsert更新方法

upsert是一种特殊的更新。要是没有文档符合更新条件，就会以这个条件创建一个新文档，假设匹配就更新。

事实上就是update的第三參数。默认就是false.

> db.analytics.find()

{ "_id" :ObjectId("56a88706308203e00e436b04"), "url" :"www.baidu.com", "pageview" : 2, "visits" : 3 }

> db.analytics.update({"url":"www.csdn.net"},{"$inc":{"visits": 1}},true)

> db.analytics.find()

{ "_id" :ObjectId("56a88706308203e00e436b04"), "url" :"www.baidu.com", "pageview" : 2, "visits" : 3 }

{ "_id" :ObjectId("56ab094c638a1346c373d5d9"), "url" :"www.csdn.net", "visits" : 1 }

save 函数

save是一个shell函数，能够文档不存在时插入，存在时更新。它仅仅有一个參数：文档

使用例如以下：

> var x=db.foo.findOne()

> x.sum = 50

50

> db.foo.save(x)

> db.foo.find()

{ "_id" :ObjectId("56a88f55308203e00e436b07"), "count" :"1", "num" : 42, "sum" : 50 }

更新很多其它的文档

默认情况下，更新仅仅能对条件的第一个文档运行操作。

要使用全部文档都得到更新，能够设置update的第4个參数为ture,默认是false

比如：

给全部特定日期过生日的用户发一份礼物，就可使用多文档更新。将gift增加到他们的账号.

>db.users.update({"birthday":"1988/11/1"},{"$set":{gift:"Happybirthday!"}},false,true)

--查看更新了多少文档。n就是这个值

> db.runCommand({getLastError : 1})

{

       "connectionId" : 13,

       "n" : 3,

       "syncMillis" : 0,

       "writtenTo" : null,

       "err" : null,

       "ok" : 1

}