Delete Documents

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Overview

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

Overview

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

A delete operation removes one or more documents from a MongoDB collection. You can perform a delete operation by using the mongoc_collection_delete_one() or mongoc_collection_delete_many() functions.

Sample Data

The examples in this guide use the restaurants collection in the sample_restaurants database from the Atlas sample datasets. To learn how to create a free MongoDB Atlas cluster and load the sample datasets, see the Get Started with Atlas guide.

Delete Operations

You can perform delete operations by using the following functions:

mongoc_collection_delete_one(), which deletes the first document that matches the search criteria
mongoc_collection_delete_many(), which deletes all documents that match the search criteria

Each delete function accepts the following parameters:

Collection: Specifies the collection to modify.
Query filter document: Specifies which collection documents to delete. For more information about query filters, see the Query Filter Documents section in the MongoDB Server manual.
Results location: Specifies a pointer to overwritable storage that will contain operation results, or NULL.
Error location: Specifies a location for an error value, or NULL.

Delete One Document

The following example uses the mongoc_collection_delete_one() function to remove a document in the restaurants collection that has a name value of "Ready Penny Inn":

bson_t *filter = BCON_NEW ("name", BCON_UTF8 ("Ready Penny Inn"));
bson_error_t error;
if (!mongoc_collection_delete_one (collection, filter, NULL, NULL, &error)) {
    printf ("Delete error: %s\n", error.message);
}
bson_destroy (filter);

Delete Multiple Documents

The following example uses the mongoc_collection_delete_many() function to remove all documents in the restaurants collection that have a borough value of "Brooklyn":

bson_t *filter = BCON_NEW ("borough", BCON_UTF8 ("Brooklyn"));
bson_error_t error;
if (!mongoc_collection_delete_many (collection, filter, NULL, NULL, &error)) {
    printf ("Delete error: %s\n", error.message);
}
bson_destroy (filter);

Customize the Delete Operation

You can modify the behavior of the mongoc_collection_delete_one() and mongoc_collection_delete_many() functions by passing a BSON document that specifies option values. The following table describes some options you can set in the document:

Field	Description
`collation`	Specifies the kind of language collation to use when comparing text. For more information, see Collation in the MongoDB Server manual. Type: `bson_t`
`writeConcern`	Sets the write concern for the operation. Defaults to the write concern of the namespace. Type: `mongoc_write_concern_t`
`let`	Specifies a document with a list of values to improve operation readability. 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. Type: `bson_t`
`comment`	A comment to attach to the operation. For more information, see the insert command fields guide in the MongoDB Server manual. Type: `bson_value_t`

The following example calls the mongoc_collection_delete_many() function to delete all documents in the restaurants collection that have a name value containing the string "Mongo". It also sets the comment option to add a comment to the operation:

bson_t *filter = BCON_NEW ("name", "{", "$regex", BCON_UTF8 ("Mongo"), "}");
bson_error_t error;
bson_t opts;
bson_init(&opts);
BCON_APPEND (&opts, "comment", BCON_UTF8 ("Deleting Mongo restaurants"));
if (!mongoc_collection_delete_many (collection, filter, &opts, NULL, &error)) {
    printf ("Delete error: %s\n", error.message);
}
bson_destroy (filter);
bson_destroy (&opts);

Tip

If you use the mongoc_collection_delete_one() function instead of mongoc_collection_delete_many() in the preceding example, the driver deletes only the first document that has a name value containing "Mongo".

API Documentation

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

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Bulk Write Operations