Creating Indexes¶
To create indexes on a MongoDB collection, execute the createIndexes
command
with mongoc_database_write_command_with_opts(). See the MongoDB
Manual entry for the createIndexes command for details.
Example¶
/* gcc example-create-indexes.c -o example-create-indexes $(pkg-config --cflags
* --libs libmongoc-1.0) */
/* ./example-create-indexes [CONNECTION_STRING [COLLECTION_NAME]] */
#include <mongoc.h>
#include <stdio.h>
#include <stdlib.h>
int
main (int argc, char *argv[])
{
mongoc_client_t *client;
mongoc_database_t *db;
const char *uristr = "mongodb://127.0.0.1/?appname=create-indexes-example";
const char *collection_name = "test";
bson_t keys;
char *index_name;
bson_t *create_indexes;
bson_t reply;
char *reply_str;
bson_error_t error;
bool r;
mongoc_init ();
if (argc > 1) {
uristr = argv[1];
}
if (argc > 2) {
collection_name = argv[2];
}
client = mongoc_client_new (uristr);
if (!client) {
fprintf (stderr, "Failed to parse URI.\n");
return EXIT_FAILURE;
}
mongoc_client_set_error_api (client, 2);
db = mongoc_client_get_database (client, "test");
/* ascending index on field "x" */
bson_init (&keys);
BSON_APPEND_INT32 (&keys, "x", 1);
index_name = mongoc_collection_keys_to_index_string (&keys);
create_indexes = BCON_NEW ("createIndexes",
BCON_UTF8 (collection_name),
"indexes",
"[",
"{",
"key",
BCON_DOCUMENT (&keys),
"name",
BCON_UTF8 (index_name),
"}",
"]");
r = mongoc_database_write_command_with_opts (
db, create_indexes, NULL /* opts */, &reply, &error);
reply_str = bson_as_json (&reply, NULL);
printf ("%s\n", reply_str);
if (!r) {
fprintf (stderr, "Error in createIndexes: %s\n", error.message);
}
bson_free (index_name);
bson_free (reply_str);
bson_destroy (&reply);
bson_destroy (create_indexes);
mongoc_database_destroy (db);
mongoc_client_destroy (client);
mongoc_cleanup ();
return r ? EXIT_SUCCESS : EXIT_FAILURE;
}