mongoc_collection_update_one - Man Page

mongoc_collection_update_one()

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:

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().

See Also

MongoDB update command documentation for more information on the update options.

mongoc_collection_update_many

mongoc_collection_replace_one

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 (int argc, char **argv)
{
   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);

   return EXIT_SUCCESS;
}

Author

MongoDB, Inc

Referenced By

mongoc_collection_replace_one(3), mongoc_collection_update_many(3).

Apr 09, 2021 1.17.5 libmongoc