Result object for database query.
A MongoCursor has two "life stages": pre- and post- query. A cursor can be created manually by calling the constructor, but it is most often created by calling MongoCollection::find(). When a cursor is created, it has not yet contacted the database, so it is in its pre-query state. In this state, the client can further specify what they want the query to do, including adding limits, skips, sorts, and more advanced options.
When the client attempts to get a result (by calling MongoCursor::next(), directly or indirectly), the cursor moves into the post-query stage. At this point, the query has been executed by the database and cannot be modified anymore.
$cursor = $collection->find()->limit(10);
// database has not yet been queried, so more search options can be added
$cursor = $cursor->sort(array("a" => 1));
// now database has been queried and more options cannot be added
// so this will throw an exception:
If the query should have the "slaveOkay" flag set, which allows reads on the slave (slaves are, by default, just for backup and unreadable). Can be overridden with MongoCursor::slaveOkay().
Set timeout in milliseconds for all database responses. To wait forever, use -1. Can be overridden with MongoCursor::timeout(). This does not cause the MongoDB server to cancel the operation, it just causes the driver to stop waiting for a response and throw a MongoCursorTimeoutException.
MongoDB core docs on » cursors.