[MongoDB]Update更新数据
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Update操作只作用于集合中存在的文档。MongoDB提供了如下方法来更新集合中的文档：
- db.collection.update()
- db.collection.updateOne() New in version 3.2
- db.collection.updateMany() New in version 3.2
- db.collection.replaceOne() New in version 3.2
你可以通过指定criteria或者filter来指定你想更新的文档：
update函数执行数据更新操作，该函数接受3个主要参数：criteria，action，options：
- 参数criteria用于指定一个查询，查询选择将要更新的目标记录。
- 参数action用于指定更新信息，也可以使用操作符来完成。
- 参数options用于指定更新文档时的选项，可选值包括：upsert和multi。upsert可以指定如果数据存在就更新，不存在就创建数据；multi选项指定是否应该更新所有匹配的文档，或者只更新第一个文档（默认行为）。
为了更好的演示，插入数据：
db.users.insertMany(
[
_id: 1,
name: "sue",
age: 19,
type: 1,
status: "P",
favorites: artist: "Picasso", food: "pizza" ,
finished: [ 17, 3 ],
badges: [ "blue", "black" ],
points: [
points: 85, bonus: 20 ,
points: 85, bonus: 10
]
,
_id: 2,
name: "bob",
age: 42,
type: 1,
status: "A",
favorites: artist: "Miro", food: "meringue" ,
finished: [ 11, 25 ],
badges: [ "green" ],
points: [
points: 85, bonus: 20 ,
points: 64, bonus: 12
]
,
_id: 3,
name: "ahn",
age: 22,
type: 2,
status: "A",
favorites: artist: "Cassatt", food: "cake" ,
finished: [ 6 ],
badges: [ "blue", "Picasso" ],
points: [
points: 81, bonus: 8 ,
points: 55, bonus: 20
]
,
_id: 4,
name: "xi",
age: 34,
type: 2,
status: "D",
favorites: artist: "Chagall", food: "chocolate" ,
finished: [ 5, 11 ],
badges: [ "Picasso", "black" ],
points: [
points: 53, bonus: 15 ,
points: 51, bonus: 15
]
,
_id: 5,
name: "xyz",
age: 23,
type: 2,
status: "D",
favorites: artist: "Noguchi", food: "nougat" ,
finished: [ 14, 6 ],
badges: [ "orange" ],
points: [
points: 71, bonus: 20
]
,
_id: 6,
name: "abc",
age: 43,
type: 1,
status: "A",
favorites: food: "pizza", artist: "Picasso" ,
finished: [ 18, 12 ],
badges: [ "black", "blue" ],
points: [
points: 78, bonus: 8 ,
points: 57, bonus: 7
]
]
)1. 字段更新操作符
1.1 覆盖更新
下面的例子使用update()函数执行更新数据操作，不包含操作符：
> db.users.find("name":"xyz");
"_id" : 5, "name" : "xyz", "age" : 23, "type" : 2, "status" : "D", "favorites" : "artist" : "Noguchi", "food" : "nougat" , "finished" : [ 14, 6 ], "badges" : [ "orange" ], "points" : [ "points" : 71, "bonus" : 20 ]
>修改之后：
> db.users.update("name":"xyz", name : "xyz", age:25, school : "xidian", type:1, favorites: artist : "Noguchi", food : "nougat", finished : [4, 5] , upsert:true);
WriteResult( "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 )
>
>
>
> db.users.find("name":"xyz");
"_id" : 5, "name" : "xyz", "age" : 25, "school" : "xidian", "type" : 1, "favorites" : "artist" : "Noguchi", "food" : "nougat" , "finished" : [ 4, 5 ] 该例覆写了集合中的文档，并保存更新后的值。
备注
任何忽略的字段都被移除（文档被覆盖）
1.2 upsert
upsert可以指定如果数据存在就更新，不存在就创建数据。
> db.users.find("name":"yoona");
>
> db.users.update("name":"yoona", name : "yoona", age:25, "school" : "xidian", type:1, favorites: artist : "Noguchi", food : "nougat", finished : [4, 5] , upsert:false);
WriteResult( "nMatched" : 0, "nUpserted" : 0, "nModified" : 0 )更新操作之前我们没有查询到yoona的任何信息，然后我们对其进行更新操作，并且upsert设置为false，表示如果更新的数据不存在，不走任何操作。更新之后，我们再次查询一下：
> db.users.find("name":"yoona");
>再次查询还是没有找到相应数据。我们设置upsert为true，表示如果数据存在则更新，如果不存在则创建该数据：
> db.users.update("name":"yoona", name : "yoona", age:25, "school" : "xidian", type:1, favorites: artist : "Noguchi", food : "nougat", finished : [4, 5] , upsert:true);
WriteResult(
"nMatched" : 0,
"nUpserted" : 1,
"nModified" : 0,
"_id" : ObjectId("57c3ad26d2cc0133a95bc583")
)
>
> db.users.find("name":"yoona");
"_id" : ObjectId("57c3ad26d2cc0133a95bc583"), "name" : "yoona", "age" : 25, "school" : "xidian", "type" : 1, "favorites" : "artist" : "Noguchi", "food" : "nougat" , "finished" : [ 4, 5 ] 1.3 $inc 增加值
操作符$inc可以为指定的键执行（原子）更新操作，如果字段存在，就将该值增加给定的增量，如果该字段不存在，就创建该字段。
> db.users.update("name":"yoona", $inc:age:2);
WriteResult( "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 )
>
>
> db.users.find(name:"yoona");
"_id" : ObjectId("57c3ad26d2cc0133a95bc583"), "name" : "yoona", "age" : 27, "school" : "xidian", "type" : 1, "favorites" : "artist" : "Noguchi", "food" : "nougat" , "finished" : [ 4, 5 ] 上面例子中将yoona用户的年龄增加两岁。
1.4 $set 设置字段值
可以使用$set操作符将某个字段设置为指定值。
> db.users.find(name:"yoona");
"_id" : ObjectId("57c3ad26d2cc0133a95bc583"), "name" : "yoona", "age" : 27, "school" : "xidian", "type" : 1, "favorites" : "artist" : "Noguchi", "food" : "nougat" , "finished" : [ 4, 5 ]
>
> db.users.update("name":"yoona", $set:school:"Massachusetts Institute of Technology");
WriteResult( "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 )
>
> db.users.find(name:"yoona");
"_id" : ObjectId("57c3ad26d2cc0133a95bc583"), "name" : "yoona", "age" : 27, "school" : "Massachusetts Institute of Technology", "type" : 1, "favorites" : "artist" : "Noguchi", "food" : "nougat" , "finished" : [ 4, 5 ]
>上面例子将yoona用户的学校改为麻省理工学院。
1.5 $unset删除指定字段
> db.users.find(name:"yoona");
"_id" : ObjectId("57c3ad26d2cc0133a95bc583"), "name" : "yoona", "age" : 27, "school" : "Massachusetts Institute of Technology", "type" : 1, "favorites" : "artist" : "Noguchi", "food" : "nougat" , "finished" : [ 4, 5 ]
>
> db.users.update("name":"yoona", $unset:school:"Massachusetts Institute of Technology");
WriteResult( "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 )
>
> db.users.find(name:"yoona");
"_id" : ObjectId("57c3ad26d2cc0133a95bc583"), "name" : "yoona", "age" : 27, "type" : 1, "favorites" : "artist" : "Noguchi", "food" : "nougat" , "finished" : [ 4, 5 ] 上面例子将yoona用户的学校删除。
1.6 $rename 重命名字段名称
格式：
$rename: <field1>: <newName1>, <field2>: <newName2>, ... 新字段名称必须不同与已经存在的字段名称
> db.users.find(name:"yoona");
"_id" : ObjectId("57c3ad26d2cc0133a95bc583"), "name" : "yoona", "age" : 27, "type" : 1, "favorites" : "artist" : "Noguchi", "food" : "nougat" , "finished" : [ 4, 5 ]
>
> db.users.update("name":"yoona", $rename: name:"userName", age:"userAge");
WriteResult( "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 )
>查询：
> db.users.find(name:"yoona");
> db.users.find(userName:"yoona");
"_id" : ObjectId("57c3ad26d2cc0133a95bc583"), "type" : 1, "favorites" : "artist" : "Noguchi", "food" : "nougat" , "finished" : [ 4, 以上是关于[MongoDB]Update更新数据的主要内容，如果未能解决你的问题，请参考以下文章