Delete Documents

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Overview

Sample Data
Delete Operations
Delete One Document
Delete Multiple Documents
Customize the Delete Operation
Example
Additional Information
API Documentation

Overview

In this guide, you can learn how to use the Java Reactive Streams driver to delete documents from a MongoDB collection by performing delete operations.

A delete operation deletes one or more documents from a MongoDB collection. You can perform a delete operation by using the deleteOne() or deleteMany() methods.

Sample Data

The examples in this guide use the sample_restaurants.restaurants collection from the Atlas sample datasets.

To learn how to create a free MongoDB Atlas cluster and load the sample datasets, see the Get Started tutorial.

Important

Project Reactor Library

This guide uses the Project Reactor library to consume Publisher instances returned by the Java Reactive Streams driver methods. To learn more about the Project Reactor library and how to use it, see Getting Started in the Reactor documentation. To learn more about how we use Project Reactor library methods in this guide, see the Write Data to MongoDB guide.

Delete Operations

You can perform delete operations in MongoDB by using the following methods:

deleteOne(), which deletes the first document that matches the search criteria
deleteMany(), which deletes all documents that match the search criteria

Each delete method requires a query filter, which specifies the search criteria that determine which documents to select for removal. For more information about query filters, see the Query Filter Documents section in the MongoDB Server manual.

Delete One Document

To delete a single document from a MongoDB collection, call the deleteOne() method and pass in your query filter. Then, pass the deleteOne() result to the static Mono.from method from Mono. Mono is a class from the Project Reactor library. In Java Reactive Streams, the driver methods return cold Publisher instances, which means that the corresponding operation does not happen unless you subscribe to the returned Publisher. This guide uses the Project Reactor library to consume them. To learn more about Mono, see Mono in the Project Reactor documentation.

The following example deletes a document from the restaurants collection that has a name value of "Ready Penny Inn":

Publisher<DeleteResult> deletePublisher = restaurants.deleteOne(
        eq("name", "Ready Penny Inn"));
Mono.from(deletePublisher).block();

Delete Multiple Documents

To delete multiple documents from a MongoDB collection, call the deleteMany() method and pass in your query filter. Then, pass the deleteMany() result to the static Mono.from method from Mono. Mono is a class from the Project Reactor library. In Java Reactive Streams, the driver methods return cold Publisher instances, which means that the corresponding operation does not happen unless you subscribe to the returned Publisher. This guide uses the Project Reactor library to consume them. To learn more about Mono, see Mono in the Project Reactor documentation.

The following example removes all documents in the restaurants collection that have a borough value of "Brooklyn":

Publisher<DeleteResult> deletePublisher = restaurants.deleteMany(
        eq("borough", "Brooklyn"));
Mono.from(deletePublisher).block();

Customize the Delete Operation

The DeleteOptions class contains methods that modify the behavior of delete methods. To use the DeleteOptions class, construct a new instance of the class, then call one or more of its methods to modify the delete operation. You can chain these method calls together. To modify the behavior of the delete operation, pass the class instance and chained method calls as the second argument to the deleteOne() or deleteMany() method.

You can use the following methods in the DeleteOptions class to modify a delete method. All methods are optional.

Method	Description
`collation (Collation collation)`	Specifies the kind of language collation to use when sorting results. For more information, see Collation in the MongoDB Server manual.
`hint (Bson hint)`	Gets or sets the index to scan for documents. For more information, see the hint statement in the MongoDB Server manual.
`hint (String hint)`	Gets or sets the index to scan for documents. For more information, see the hint statement in the MongoDB Server manual.
`let (Bson variables)`	A map of parameter names and values. Values must be constant or closed expressions that don't reference document fields. For more information, see the let statement in the MongoDB Server manual.
`comment (BsonValue comment)`	A comment to attach to the operation. For more information, see the delete command fields guide in the MongoDB Server manual for more information.
`comment (String comment)`	A comment to attach to the operation. For more information, see the delete command fields guide in the MongoDB Server manual for more information.

Example

The following code uses the deleteMany() method to delete all documents in the restaurants collection with a name value that includes the string "Mongo". It also uses the comment method to add a comment to the operation.

Publisher<DeleteResult> deletePublisher = restaurants.deleteMany(
        regex("name", "Mongo"),
        new DeleteOptions().comment("Deleting Mongo restaurants"));
Mono.from(deletePublisher).block();

Additional Information

For runnable code examples of inserting documents with the Java Reactive Streams driver, see the Write Data to MongoDB guide.

API Documentation

To learn more about any of the methods or types discussed in this guide, see the following API documentation:

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