Deleting a Document

The Basics

The following code example creates a new mongoc_client_t that we will use to communicate with MongoDB. The Connection String URI component is quite comprehensive.

Using our mongoc_client_t, we get a handle to a mongoc_collection_t which represents the remote collection. We create a new document, initialized with an _id and a field named hello and insert it into the test.test collection. Immediately after, we remove the document matching the _id we inserted.

Lastly, we release all of our heap allocated structures.

<file>example4.c</file> Removing a document from a collection.


#include 
#include 

int
main (int   argc,
      char *argv[])
{
    mongoc_client_t *client;
    mongoc_collection_t *collection;
    mongoc_cursor_t *cursor;
    bson_error_t error;
    bson_oid_t oid;
    bson_t *doc;

    mongoc_init ();

    client = mongoc_client_new ("mongodb://localhost:27017/");
    collection = mongoc_client_get_collection (client, "test", "test");

    doc = bson_new ();
    bson_oid_init (&oid, NULL);
    BSON_APPEND_OID (doc, "_id", &oid);
    BSON_APPEND_UTF8 (doc, "hello", "world");

    if (!mongoc_collection_insert (collection, MONGOC_INSERT_NONE, doc, NULL, &error)) {
        printf ("Insert failed: %s\n", error.message);
    }

    bson_destroy (doc);

    doc = bson_new ();
    BSON_APPEND_OID (doc, "_id", &oid);

    if (!mongoc_collection_delete (collection, MONGOC_DELETE_SINGLE_REMOVE, doc, NULL, &error)) {
        printf ("Delete failed: %s\n", error.message);
    }

    bson_destroy (doc);
    mongoc_collection_destroy (collection);
    mongoc_client_destroy (client);

    return 0;
}
]]>

Let's use GCC and pkg-config to compile example3.c.

gcc -o example4 example4.c $(pkg-config --cflags --libs libmongoc-1.0)

When using the MongoDB C Driver, you must call mongoc_init() at the beginning of your application. This allows the driver to initialize it's required subsystems. Failure to do so will result in a runtime crash.

Now let's run it!

./example4