Scroll to navigation

MONGOC_COLLECTION_UPDATE_ONE(3) libmongoc MONGOC_COLLECTION_UPDATE_ONE(3)

SYNOPSIS

bool
mongoc_collection_update_one (mongoc_collection_t *collection,


                              const bson_t *selector,


                              const bson_t *update,


                              const bson_t *opts,


                              bson_t *reply,


                              bson_error_t *error);


PARAMETERS


opts may be NULL or a BSON document with additional command options:

  • writeConcern: Construct a mongoc_write_concern_t <> and use mongoc_write_concern_append() <> to add the write concern to opts. See the example code for mongoc_client_write_command_with_opts() <>.
  • sessionId: First, construct a mongoc_client_session_t <> with mongoc_client_start_session() <>. You can begin a transaction with mongoc_client_session_start_transaction() <>, optionally with a mongoc_transaction_opt_t <> that overrides the options inherited from collection, and use mongoc_client_session_append() <> to add the session to opts. See the example code for mongoc_client_session_t <>.
  • validate: Construct a bitwise-or of all desired bson_validate_flags_t <https://www.mongoc.org/libbson/current/bson_validate_flags_t.html>. Set to false to skip client-side validation of the provided BSON documents.
  • comment: A bson_value_t <https://www.mongoc.org/libbson/current/bson_value_t.html> specifying the comment to attach to this command. The comment will appear in log messages, profiler output, and currentOp output. Requires MongoDB 4.4 or later.
  • bypassDocumentValidation: Set to true to skip server-side schema validation of the provided BSON documents.
  • collation: Configure textual comparisons. See Setting Collation Order <https://www.mongodb.com/docs/languages/c/c-driver/current/libmongoc/guides/bulk/#setting-collation-order>, and the MongoDB Manual entry on Collation <https://www.mongodb.com/docs/manual/reference/collation/>. Collation requires MongoDB 3.2 or later, otherwise an error is returned.
  • hint: A document or string that specifies the index to use to support the query predicate.
  • upsert: When true, creates a new document if no document matches the query.
  • let: A BSON document consisting of any number of parameter names, each followed by definitions of constants in the MQL Aggregate Expression language.
  • arrayFilters: An array of filters specifying to which array elements an update should apply.
  • sort: Specify a sort order when matching documents.

DESCRIPTION

This function updates at most one document in collection that matches selector.

To update multiple documents see mongoc_collection_update_many() <>.

If you pass a non-NULL reply, it is filled out with fields matchedCount, modifiedCount, and optionally upsertedId if applicable. If there is a server error then reply contains either a "writeErrors" array with one subdocument or a "writeConcernErrors" array. The reply must be freed with bson_destroy() <https://www.mongoc.org/libbson/current/bson_destroy.html>.

ERRORS

Errors are propagated via the error parameter.

RETURNS

Returns true if successful. Returns false and sets error if there are invalid arguments or a server or network error.

A write concern timeout or write concern error is considered a failure.

EXAMPLE

example-update.c

#include <mongoc/mongoc.h>
int
main(void)
{


   mongoc_init();


   bson_t *to_insert = BCON_NEW("_id", BCON_INT32(1));


   bson_t *selector = BCON_NEW("_id", "{", "$gt", BCON_INT32(0), "}");


   bson_t *update = BCON_NEW("$set", "{", "x", BCON_INT32(1), "}");


   const bson_t *next_doc;


   char *to_str;


   bson_error_t error = {0};


   mongoc_cursor_t *cursor;


   mongoc_client_t *client;


   mongoc_collection_t *coll;


   const char *uri_string = "mongodb://localhost:27017/?appname=example-update";


   mongoc_uri_t *uri = mongoc_uri_new_with_error(uri_string, &error);


   if (!uri) {


      fprintf(stderr,


              "failed to parse URI: %s\n"


              "error message:       %s\n",


              uri_string,


              error.message);


      return EXIT_FAILURE;


   }


   client = mongoc_client_new_from_uri(uri);


   if (!client) {


      return EXIT_FAILURE;


   }


   coll = mongoc_client_get_collection(client, "db", "example_coll");


   mongoc_client_set_error_api(client, 2);


   /* insert a document */


   if (!mongoc_collection_insert_one(coll, to_insert, NULL, NULL, &error)) {


      fprintf(stderr, "insert failed: %s\n", error.message);


      return EXIT_FAILURE;


   }


   if (!mongoc_collection_update_one(coll, selector, update, NULL, NULL, &error)) {


      fprintf(stderr, "update failed: %s\n", error.message);


      return EXIT_FAILURE;


   }


   to_str = bson_as_relaxed_extended_json(to_insert, NULL);


   printf("inserted: %s\n", to_str);


   bson_free(to_str);


   cursor = mongoc_collection_find_with_opts(coll, selector, NULL, NULL);


   BSON_ASSERT(mongoc_cursor_next(cursor, &next_doc));


   printf("after update, collection has the following document:\n");


   to_str = bson_as_relaxed_extended_json(next_doc, NULL);


   printf("%s\n", to_str);


   bson_free(to_str);


   BSON_ASSERT(mongoc_collection_drop(coll, NULL));


   bson_destroy(to_insert);


   bson_destroy(update);


   bson_destroy(selector);


   mongoc_collection_destroy(coll);


   mongoc_uri_destroy(uri);


   mongoc_client_destroy(client);


   mongoc_cleanup();


   return EXIT_SUCCESS;
}


See also:

MongoDB update command documentation <https://www.mongodb.com/docs/manual/reference/command/update/> for more information on the update options.

mongoc_collection_update_many() <>

mongoc_collection_replace_one() <>



Author

MongoDB, Inc

Copyright

2009-present, MongoDB, Inc.

November 26, 2025 2.2.0