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在 MongoDB 中更新数据

在本指南中,您将更新文档中的一个字段。

所需时间10分钟

  • A到您的MongoDB部署的连接字符串

  • 已加载到您的集群中的示例数据集

  • 已安装的MongoDB驱动程序

1
1

以下类列出了您的文档将拥有的所有字段名称和数据类型。

CrudUpdate.cs
1// class that maps to the fields of a document in the sample_guides.comets collection
2class Comet {
3 public ObjectId Id { get; set; }
4 public string Name { get; set; }
5 public string OfficialName { get; set; }
6 public double OrbitalPeriod { get; set; }
7 public double Radius { get; set; }
8 public double Mass { get; set; }
9}
2

在C#中,您将字段映射到类的属性,属性名通常为大写。但是,您应该使用驼峰命名法插入数据。为了使驱动程序自动将字段从大写转换为驼峰命名法,创建一个ConventionPack 并注册 CamelCase 命名约定。

CrudUpdate.cs
1// instruct the driver to camelCase the fields in MongoDB
2var pack = new ConventionPack { new CamelCaseElementNameConvention() };
3ConventionRegistry.Register("elementNameConvention", pack, x => true);
3

提示

以下是最小化代码的概要,用于连接到MongoDB。您将在接下来的几个步骤中添加代码来插入数据。

在行5,将URI字符串替换为您的自己的Atlas连接字符串。

CrudUpdate.cs
1using MongoDB.Bson;
2using MongoDB.Driver;
3
4// Replace the uri string with your MongoDB deployment's connection string.
5var uri = "mongodb+srv://<user>:<password>@<cluster-url>?retryWrites=true&writeConcern=majority";
6
7// instruct the driver to camelCase the fields in MongoDB
8var pack = new ConventionPack { new CamelCaseElementNameConvention() };
9ConventionRegistry.Register("elementNameConvention", pack, x => true);
10
11var client = new MongoClient(uri);
12
13// database and collection code goes here
14// update code goes here
15// amount updated code goes here
16
17// class that maps to the fields of a document in the sample_guides.comets collection
18class Comet
19{
20 public ObjectId Id { get; set; }
21 public string Name { get; set; }
22 public string OfficialName { get; set; }
23 public double OrbitalPeriod { get; set; }
24 public double Radius { get; set; }
25 public double Mass { get; set; }
26}

提示

以下是最小化代码的概要,用于连接到MongoDB。您将在接下来的几个步骤中添加代码来插入数据。

在行13,将URI字符串替换为您的自己的Atlas连接字符串。

crud-update.go
1package main
2
3import (
4 "context"
5 "log"
6 "os"
7
8 "go.mongodb.org/mongo-driver/mongo"
9 "go.mongodb.org/mongo-driver/mongo/options"
10)
11
12func main() {
13 uri := "mongodb+srv://<user>:<password>@<cluster-url>?retryWrites=true&writeConcern=majority"
14
15 client, err := mongo.Connect(context.TODO(), options.Client().ApplyURI(uri))
16 if err != nil {
17 panic(err)
18 }
19
20 client, err := mongo.Connect(context.TODO(), options.Client().ApplyURI(uri))
21 if err != nil {
22 panic(err)
23 }
24 defer func() {
25 if err = client.Disconnect(context.TODO()); err != nil {
26 panic(err)
27 }
28 }()
29
30 // database and colletion code goes here
31 // update code goes here
32 // amount update code goes here
33}

提示

以下是最小化代码的概要,用于连接到MongoDB。您将在接下来的几个步骤中添加代码来插入数据。

在行14,将URI字符串替换为您的自己的Atlas连接字符串。

CrudUpdate.java
1import com.mongodb.client.MongoClient;
2import com.mongodb.client.MongoClients;
3import com.mongodb.client.MongoCollection;
4import com.mongodb.client.MongoDatabase;
5import com.mongodb.client.result.UpdateResult;
6import com.mongodb.client.model.Filters;
7import com.mongodb.client.model.Updates;
8
9import org.bson.Document;
10import org.bson.conversions.Bson;
11
12public class CrudUpdate {
13 public static void main(String[] args) {
14 String uri = "mongodb+srv://<user>:<password>@<cluster-url>?retryWrites=true&writeConcern=majority";
15
16 try (MongoClient mongoClient = MongoClients.create(uri)) {
17 // database and collection code goes here
18 // update code goes here
19 // amount updated code goes here
20 }
21 }
22}

提示

以下是最小化代码的概要,用于连接到MongoDB。您将在接下来的几个步骤中添加代码来插入数据。

在行4,将URI字符串替换为您的自己的Atlas连接字符串。

crud-update.js
1const { MongoClient } = require("mongodb");
2// Replace the uri string with your MongoDB deployment's connection string.
3const uri =
4 "mongodb+srv://<user>:<password>@<cluster-url>?retryWrites=true&writeConcern=majority";
5
6const client = new MongoClient(uri);
7
8async function run() {
9 try {
10 await client.connect();
11 // database and collection code goes here
12 // update code goes here
13 // amount deleted code goes here
14 } finally {
15 // Ensures that the client will close when you finish/error
16 await client.close();
17 }
18}
19run().catch(console.dir);

提示

以下是最小化代码的概要,用于连接到MongoDB。您将在接下来的几个步骤中添加代码来插入数据。

在行4,将URI字符串替换为您的自己的Atlas连接字符串。

crud_update.py
1from pymongo import MongoClient
2
3# Replace the uri string with your MongoDB deployment's connection string.
4uri = "mongodb+srv://<user>:<password>@<cluster-url>?retryWrites=true&writeConcern=majority"
5
6client = MongoClient(uri)
7
8# database and collection code goes here
9# update code goes here
10# amount updated code goes here
11
12# Close the connection to MongoDB when you're done.
13client.close()

提示

mongodb+srv

请确保您已使用srv选项安装了PyMongo。

python3 -m pip install "pymongo[srv]"
2

切换到您要操作的数据库和集合。在本例中,您将使用sample_guides数据库和comets集合。

CrudUpdate.cs
// database and collection code goes here
var db = client.GetDatabase("sample_guides");
var coll = db.GetCollection<Comet>("comets");
crud-update.go
1// database and colletion code goes here
2db := client.Database("sample_guides")
3coll := db.Collection("comets")
CrudUpdate.java
1// database and collection code goes here
2MongoDatabase db = mongoClient.getDatabase("sample_guides");
3MongoCollection<Document> coll = db.getCollection("comets");
crud-update.js
// database and collection code goes here
const db = client.db("sample_guides");
const coll = db.collection("comets");
crud_update.py
# database and collection code goes here
db = client.sample_guides
coll = db.comets
3

上一篇指南中,您向《comets》集合中插入了文档。现在,您需要对这些文档进行更新。所有字段都是以公制单位表示,除了《radius》字段,它是以英制表示。

以下示例使用更新文档将所有文档中的《radius》字段从公制系统转换为英制系统。

提示

转换

1英里 = 1.60934公里

MongoDB C# 驱动程序包括Builders,这些可以简化查询和其他操作的创建过程。在这里,您使用《Filter.Empty》和《Update.Mul》构建器来构建查询文档和更新文档。

CrudUpdate.cs
// update code goes here
var filter = Builders<Comet>.Filter.Empty;
var update = Builders<Comet>.Update.Mul("radius", 1.60934);
var result = coll.UpdateMany(filter, update);
crud-update.go
1// database and colletion code goes here
2db := client.Database("sample_guides")
3coll := db.Collection("comets")
4
5// update code goes here
6filter := bson.D{{}}
7update := bson.D{{"$mul", bson.D{{"radius", 1.60934}}}}
8
9result, err := coll.UpdateMany(context.TODO(), filter, update)
10if err != nil {
11 panic(err)
12}

MongoDB Java 驱动程序包括Builders,这些可以简化查询(和其他操作)的创建过程。在这里,您使用《Filters.empty》和《Updates.mul》构建器来构建查询文档。

CrudUpdate.java
1// update code goes here
2Bson filter = Filters.empty();
3Bson update = Updates.mul("radius", 1.60934);
4UpdateResult result = coll.updateMany(filter, update);
crud-update.js
// update code goes here
const filter = { };
const updateDoc = {
$mul: {
radius: 1.60934
}
};
const result = await coll.updateMany(filter, updateDoc);
crud_update.py
# update code goes here
doc = {
'$mul': {'radius': 1.60934}
}
result = coll.update_many({}, doc)
4

MongoDB中的许多写操作返回一个包含操作信息的结果对象。

对于更新操作,结果对象将包含成功更新的文档修改计数。在这里,您访问此属性并打印它们。

CrudUpdate.cs
// display the results of your operation
Console.WriteLine($"Number of documents updated: {result.ModifiedCount}");
crud-update.go
1// display the results of your operation
2fmt.Printf("Number of documents updated: %d", result.ModifiedCount)
CrudUpdate.java
1// display the results of your operation
2System.out.println("Number of documents updated: " + result.getModifiedCount());
crud-update.js
// display the results of your operation
console.log("Number of documents updated: " + result.modifiedCount);
crud_update.py
# display the results of your operation
print("Number of documents updated: ", result.modified_count)
5

以下是完整的代码和示例输出。

CrudUpdate.cs
1using MongoDB.Bson;
2using MongoDB.Driver;
3using MongoDB.Bson.Serialization.Conventions;
4
5// Replace the uri string with your MongoDB deployment's connection string.
6var uri = "mongodb+srv://<user>:<password>@<cluster-url>?retryWrites=true&writeConcern=majority";
7
8// instruct the driver to camelCase the fields in MongoDB
9var pack = new ConventionPack { new CamelCaseElementNameConvention() };
10ConventionRegistry.Register("elementNameConvention", pack, x => true);
11
12var client = new MongoClient(uri);
13
14// database and collection code goes here
15var db = client.GetDatabase("sample_guides");
16var coll = db.GetCollection<Comet>("comets");
17
18// update code goes here
19var filter = Builders<Comet>.Filter.Empty;
20var update = Builders<Comet>.Update.Mul("radius", 1.60934);
21var result = coll.UpdateMany(filter, update);
22
23// display the results of your operation
24Console.WriteLine($"Number of documents updated: {result.ModifiedCount}");
25
26// class that maps to the fields of a document in the sample_guides.comets collection
27class Comet
28{
29 public ObjectId Id { get; set; }
30 public string Name { get; set; }
31 public string OfficialName { get; set; }
32 public double OrbitalPeriod { get; set; }
33 public double Radius { get; set; }
34 public double Mass { get; set; }
35}
Number of documents updated: 3
crud-update.go
1package main
2
3import (
4 "context"
5 "fmt"
6
7 "go.mongodb.org/mongo-driver/bson"
8 "go.mongodb.org/mongo-driver/mongo"
9 "go.mongodb.org/mongo-driver/mongo/options"
10)
11
12func main() {
13 uri := "mongodb+srv://<user>:<password>@<cluster-url>?retryWrites=true&writeConcern=majority"
14
15 client, err := mongo.Connect(context.TODO(), options.Client().ApplyURI(uri))
16 if err != nil {
17 panic(err)
18 }
19
20 defer func() {
21 if err = client.Disconnect(context.TODO()); err != nil {
22 panic(err)
23 }
24 }()
25
26 // database and colletion code goes here
27 db := client.Database("sample_guides")
28 coll := db.Collection("comets")
29
30 // update code goes here
31 filter := bson.D{{}}
32 update := bson.D{{"$mul", bson.D{{"radius", 1.60934}}}}
33
34 result, err := coll.UpdateMany(context.TODO(), filter, update)
35 if err != nil {
36 panic(err)
37 }
38
39 // display the results of your operation
40 fmt.Printf("Number of documents updated: %d", result.ModifiedCount)
41}
Number of documents updated: 3
CrudUpdate.java
1import com.mongodb.client.MongoClient;
2import com.mongodb.client.MongoClients;
3import com.mongodb.client.MongoCollection;
4import com.mongodb.client.MongoDatabase;
5import com.mongodb.client.result.UpdateResult;
6import com.mongodb.client.model.Filters;
7import com.mongodb.client.model.Updates;
8
9import org.bson.Document;
10import org.bson.conversions.Bson;
11
12public class CrudUpdate {
13 public static void main(String[] args) {
14 String uri = "mongodb+srv://<user>:<password>@<cluster-url>?retryWrites=true&writeConcern=majority";
15
16 try (MongoClient mongoClient = MongoClients.create(uri)) {
17 // database and collection code goes here
18 MongoDatabase db = mongoClient.getDatabase("sample_guides");
19 MongoCollection<Document> coll = db.getCollection("comets");
20
21 // update code goes here
22 Bson filter = Filters.empty();
23 Bson update = Updates.mul("radius", 1.60934);
24 UpdateResult result = coll.updateMany(filter, update);
25
26 // display the results of your operation
27 System.out.println("Number of documents updated: " + result.getModifiedCount());
28 }
29 }
30}
Number of documents updated: 3
crud-update.js
1const { MongoClient } = require("mongodb");
2
3// Replace the uri string with your MongoDB deployment's connection string.
4const uri =
5 "mongodb+srv://<user>:<password>@<cluster-url>?retryWrites=true&writeConcern=majority";
6
7const client = new MongoClient(uri);
8
9async function run() {
10 try {
11 await client.connect();
12 // database and collection code goes here
13 const db = client.db("sample_guides");
14 const coll = db.collection("comets");
15
16 // update code goes here
17 const filter = {};
18 const updateDoc = {
19 $mul: {
20 radius: 1.60934,
21 },
22 };
23
24 const result = await coll.updateMany(filter, updateDoc);
25
26 // display the results of your operation
27 console.log("Number of documents updated: " + result.modifiedCount);
28 } finally {
29 // Ensures that the client will close when you finish/error
30 await client.close();
31 }
32}
33run().catch(console.dir);
Number of documents updated: 3
crud_update.py
1from pymongo import MongoClient
2
3# Replace the uri string with your MongoDB deployment's connection string.
4uri = "mongodb+srv://<user>:<password>@<cluster-url>?retryWrites=true&writeConcern=majority"
5
6client = MongoClient(uri)
7
8# database and collection code goes here
9db = client.sample_guides
10coll = db.comets
11
12# update code goes here
13doc = {"$mul": {"radius": 1.60934}}
14result = coll.update_many({}, doc)
15
16# display the results of your operation
17print("Number of documents updated: ", result.modified_count)
18
19# Close the connection to MongoDB when you're done.
20client.close()
Number of documents updated: 3

如果您已经完成本指南,您已在MongoDB中更新了数据。

在下一次指南中,您将学习如何在MongoDB中删除文档。

查看以下资源,以获取关于此处展示的概念的更深入信息

接下来是什么
从 MongoDB 删除数据
10分钟

指定从MongoDB中删除哪些文档。

入门指南
章节2
CRUD
  • 添加 MongoDB 驱动程序
  • 在 MongoDB 中读取数据
  • 使用查询从 MongoDB 读取数据
  • 使用运算符和组合查询读取数据
  • 将数据插入到 MongoDB
  • 在 MongoDB 中更新数据
  • 从 MongoDB 删除数据