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C Driver

Write Data to MongoDB

On this page

  • Overview
  • Sample Application
  • Insert One
  • Insert Multiple
  • Update One
  • Update Multiple
  • Delete One
  • Delete Multiple
  • Bulk Write

Overview

On this page, you can see copyable code examples that show common functions you can use to write data to MongoDB with the C driver.

Tip

To learn more about any of the functions shown on this page, see the link provided in each section.

To use an example from this page, copy the code example into the sample application or your own application. Be sure to replace all placeholders in the code examples, such as <connection string URI>, with the relevant values for your MongoDB deployment.

Sample Application

You can use the following sample application to test the code examples on this page. To use the sample application, perform the following steps:

  1. Ensure you have the C driver installed.

  2. Copy the following code and paste it into a new .c file.

  3. Copy a code example from this page and paste it on the specified lines in the file.

1#include <bson/bson.h>
2#include <mongoc/mongoc.h>
3#include <stdio.h>
4
5int
6main (void)
7{
8    mongoc_client_t *client;
9    mongoc_collection_t *collection;
10    char *str;
11    bson_error_t error;
12
13    mongoc_init ();
14
15    client =
16        mongoc_client_new ("<connection string URI>");
17    collection =
18        mongoc_client_get_collection (client, "<database name>", "collection name");
19
20    // Start example code here
21
22    // End example code here
23
24    mongoc_collection_destroy (collection);
25    mongoc_client_destroy (client);
26    mongoc_cleanup ();
27
28    return EXIT_SUCCESS;
29}

Insert One

The following code shows how to insert a single document into a collection:

bson_t *document = BCON_NEW ("<field name>", BCON_UTF8 ("<value>"));
bson_error_t error;
if (!mongoc_collection_insert_one (
    collection, document, NULL, NULL, &error)) {
    fprintf (stderr, "Insert one operation failed: %s\n", error.message);
}
bson_destroy (document);

To learn more about the mongoc_collection_insert_one() function, see the Insert Documents guide.

Insert Multiple

The following code shows how to insert multiple documents into a collection:

size_t num_docs = 2;
bson_t *docs[num_docs];
docs[0] = BCON_NEW ("<field name>", BCON_UTF8 ("<value>"));
docs[1] = BCON_NEW ("<field name>", BCON_UTF8 ("<value>"));
bson_error_t error;
if (!mongoc_collection_insert_many (collection, (const bson_t **) docs, num_docs, NULL, NULL, &error)) {
    fprintf (stderr, "Insert many operation failed: %s\n", error.message);
}
bson_destroy (docs[0]);
bson_destroy (docs[1]);

To learn more about the mongoc_collection_insert_many() function, see the Insert Documents guide.

Update One

The following code shows how to update a single document in a collection by creating or editing a field:

bson_t *query = BCON_NEW ("<field to match>", BCON_UTF8 ("<value to match>"));
bson_t *update = BCON_NEW ("$set", "{", "<field name>", BCON_UTF8 ("<value>"), "}");
bson_error_t error;
if (!mongoc_collection_update_one (collection, query, update, NULL, NULL, &error)) {
    fprintf (stderr, "Update one operation failed: %s\n", error.message);
}
bson_destroy (query);
bson_destroy (update);

To learn more about the mongoc_collection_update_one() function, see the Update Documents guide.

Update Multiple

The following code shows how to update multiple documents in a collection by creating or editing a field:

bson_t *query = BCON_NEW ("<field to match>", BCON_UTF8 ("<value to match>"));
bson_t *update = BCON_NEW ("$set", "{", "<field name>", BCON_UTF8 ("<value>"), "}");
bson_error_t error;
if (!mongoc_collection_update_many (collection, query, update, NULL, NULL, &error)) {
    fprintf (stderr, "Update many operation failed: %s\n", error.message);
}
bson_destroy (query);
bson_destroy (update);

To learn more about the mongoc_collection_update_many() function, see the Update Documents guide.

Delete One

The following code shows how to delete a single document in a collection:

bson_t *filter = BCON_NEW ("<field name>", BCON_UTF8 ("<value>"));
bson_error_t error;
if (!mongoc_collection_delete_one (collection, filter, NULL, NULL, &error)) {
    fprintf (stderr, "Delete error: %s\n", error.message);
}
bson_destroy (filter);

To learn more about the mongoc_collection_delete_one() function, see the Delete Documents guide.

Delete Multiple

The following code shows how to delete multiple documents in a collection:

bson_t *filter = BCON_NEW ("<field name>", BCON_UTF8 ("<value>"));
bson_error_t error;
if (!mongoc_collection_delete_many (collection, filter, NULL, NULL, &error)) {
    fprintf (stderr, "Delete error: %s\n", error.message);
}
bson_destroy (filter);

To learn more about the mongoc_collection_delete_many() function, see the Delete Documents guide.

Bulk Write

The following code shows how to perform multiple write operations in a single bulk operation:

bson_error_t error;
mongoc_bulk_operation_t *bulk =
   mongoc_collection_create_bulk_operation_with_opts (collection, NULL);
bson_t *insert_doc = BCON_NEW (
    "<field name>", BCON_UTF8 ("<value>"),
    "<field name>", BCON_UTF8 ("<value>"),
    "<field name>", BCON_UTF8 ("<value>"),
    "<field name>", BCON_UTF8 ("<value>")
);
mongoc_bulk_operation_insert(bulk, insert_doc);
bson_destroy (insert_doc);
    
bson_t *query = BCON_NEW ("<field to match>", BCON_UTF8 ("<value to match>"));
bson_t *update = BCON_NEW ("$set", "{", "<field name>", BCON_UTF8 ("<value>"), "}");
mongoc_bulk_operation_update_one(bulk, query, update, false);
bson_destroy(query);
bson_destroy(update);
bool result = mongoc_bulk_operation_execute(bulk, NULL, &error);
if (!result) {
    fprintf (stderr, "Bulk operation error: %s\n", error.message);
}
mongoc_bulk_operation_destroy (bulk);

To learn more about the mongoc_collection_bulk_operation_execute() function, see the Bulk Write Operations guide.

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