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

•   collection: A mongoc_collection_t.

•   selector: A bson_t containing the query to match the document for updating.

•   update: A bson_t containing the update to perform. If updating with a pipeline, a bson_t array.

•   reply: A maybe-NULL pointer to overwritable storage for a bson_t to contain the results.

•   error: An optional location for a bson_error_t or NULL.

    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. Set to false to skip client-side validation of the provided BSON documents.

•   comment: A bson_value_t 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, and the MongoDB Manual entry on 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().

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 for more information on the update options.

mongoc_collection_update_many()

mongoc_collection_replace_one()

AUTHOR
MongoDB, Inc

COPYRIGHT
2009-present, MongoDB, Inc.