Delete Documents

Overview

在本节中，我们将向您展示如何调用写入操作，以从 MongoDB database 的集合中删除文档。

删除

如果要从集合中删除现有文档，可以使用 deleteOne()删除一个文档，或使用deleteMany()删除一个或多个文档。这些方法接受与要删除的文档相匹配的查询文档。

注意

如果应用程序在删除后使用有关已删除文档的信息，则可以使用集合.findOneAndDelete()方法，该方法具有与 deleteOne() 类似的接口，但也会返回已删除的文档。

您可以通过 JSON 对象中的deleteOne()或deleteMany()写入操作指定要删除的一个或多个文档，如下所示：

const doc = {
  pageViews: {
    $gt: 10,
    $lt: 32768
  }
};

要使用deleteOne()方法删除第一个匹配文档，或使用deleteMany()方法删除所有匹配文档，请将文档作为方法参数传递：

const deleteResult = await myColl.deleteOne(doc);
const deleteManyResult = await myColl.deleteMany(doc);

您可以通过访问上述每个方法调用结果的deletedCount字段来输出该操作删除的文档数量，如下所示：

console.dir(deleteResult.deletedCount);
console.dir(deleteManyResult.deletedCount);

如果删除操作成功，这些声明会打印关联操作删除的文档数。

deleteOne() 示例：完整文件

注意

设置示例

此示例使用连接 URI 连接到MongoDB实例。要学习；了解有关连接到MongoDB实例的更多信息，请参阅连接到MongoDB指南。此示例还使用Atlas示例数据集包含的 sample_mflix数据库中的 movies集合。您可以按照Atlas入门指南，将它们加载到MongoDB Atlas免费套餐上的数据库中。

注意

无Typescript特定功能

以下代码示例使用JavaScript。驾驶员没有与此使用案例相关的Typescript特定功能。

以下代码是一个完整的独立运行文件，用于执行删除一个操作：

1 // Delete a document
2 
3 import { MongoClient } from "mongodb";
4 
5 // Replace the uri string with your MongoDB deployment's connection string
6 const uri = "<connection string uri>";
7 
8 const client = new MongoClient(uri);
9 
10 async function run() {
11   try {
12     const database = client.db("sample_mflix");
13     const movies = database.collection("movies");
14 
15     /* Delete the first document in the "movies" collection that matches
16     the specified query document */
17     const query = { title: "Annie Hall" };
18     const result = await movies.deleteOne(query);
19 
20     /* Print a message that indicates whether the operation deleted a
21     document */
22     if (result.deletedCount === 1) {
23       console.log("Successfully deleted one document.");
24     } else {
25       console.log("No documents matched the query. Deleted 0 documents.");
26     }
27   } finally {
28     // Close the connection after the operation completes
29     await client.close();
30   }
31 }
32 // Run the program and print any thrown exceptions
33 run().catch(console.dir);

运行上述示例将产生以下输出：

Successfully deleted one document.

如果多次运行该示例，则代码会生成以下输出，因为您在第一次运行中删除了匹配的文档：

No documents matched the query. Deleted 0 documents.

deleteMany() 示例：完整文件

注意

设置示例

以下代码是一个完整的独立运行文件，用于执行删除多个操作：

1 // Delete multiple documents
2 
3 import { MongoClient } from "mongodb";
4 
5 // Replace the uri string with your MongoDB deployment's connection string.
6 const uri = "<connection string uri>";
7 
8 const client = new MongoClient(uri);
9 
10 async function run() {
11   try {
12     const database = client.db("sample_mflix");
13     const movies = database.collection("movies");
14 
15     /* Delete all documents that match the specified regular
16     expression in the title field from the "movies" collection */
17     const query = { title: { $regex: "Santa" } };
18     const result = await movies.deleteMany(query);
19 
20     // Print the number of deleted documents
21     console.log("Deleted " + result.deletedCount + " documents");
22   } finally {
23     // Close the connection after the operation completes
24     await client.close();
25   }
26 }
27 // Run the program and print any thrown exceptions
28 run().catch(console.dir);

1 // Delete multiple documents
2 
3 import { MongoClient } from "mongodb";
4 
5 // Replace the uri string with your MongoDB deployment's connection string
6 const uri = "<connection string uri>";
7 
8 const client = new MongoClient(uri);
9 
10 async function run() {
11   try {
12     const database = client.db("sample_mflix");
13     const movies = database.collection("movies");
14 
15     /* Delete all documents that match the specified regular
16     expression in the title field from the "movies" collection */
17     const result = await movies.deleteMany({ title: { $regex: "Santa" } });
18     
19     // Print the number of deleted documents
20     console.log("Deleted " + result.deletedCount + " documents");
21   } finally {
22     // Close the connection after the operation completes
23     await client.close();
24   }
25 }
26 // Run the program and print any thrown exceptions
27 run().catch(console.dir);

首次运行上述示例会产生以下输出：

Deleted 19 documents

如果多次运行该示例，您将看到以下输出，因为您在第一次运行时删除了匹配的文档：

Deleted 0 documents

API 文档

要进一步了解本指南所讨论的任何类型或方法，请参阅以下 API 文档：

后退

更新数组

来年

批量写入操作

1	// Delete a document
2
3	import { MongoClient } from "mongodb";
4
5	// Replace the uri string with your MongoDB deployment's connection string
6	const uri = "<connection string uri>";
7
8	const client = new MongoClient(uri);
9
10	async function run() {
11	try {
12	const database = client.db("sample_mflix");
13	const movies = database.collection("movies");
14
15	/* Delete the first document in the "movies" collection that matches
16	the specified query document */
17	const query = { title: "Annie Hall" };
18	const result = await movies.deleteOne(query);
19
20	/* Print a message that indicates whether the operation deleted a
21	document */
22	if (result.deletedCount === 1) {
23	console.log("Successfully deleted one document.");
24	} else {
25	console.log("No documents matched the query. Deleted 0 documents.");
26	}
27	} finally {
28	// Close the connection after the operation completes
29	await client.close();
30	}
31	}
32	// Run the program and print any thrown exceptions
33	run().catch(console.dir);

1	// Delete multiple documents
2
3	import { MongoClient } from "mongodb";
4
5	// Replace the uri string with your MongoDB deployment's connection string.
6	const uri = "<connection string uri>";
7
8	const client = new MongoClient(uri);
9
10	async function run() {
11	try {
12	const database = client.db("sample_mflix");
13	const movies = database.collection("movies");
14
15	/* Delete all documents that match the specified regular
16	expression in the title field from the "movies" collection */
17	const query = { title: { $regex: "Santa" } };
18	const result = await movies.deleteMany(query);
19
20	// Print the number of deleted documents
21	console.log("Deleted " + result.deletedCount + " documents");
22	} finally {
23	// Close the connection after the operation completes
24	await client.close();
25	}
26	}
27	// Run the program and print any thrown exceptions
28	run().catch(console.dir);