(PECL mongo >=0.9.0)
MongoCursor::hasNext — Checks if there are any more elements in this cursor
锟剿猴拷锟斤拷没锟叫诧拷锟斤拷锟斤拷
Returns if there is another element.
Throws MongoConnectionException if it cannot reach the database and MongoCursorTimeoutException if the timeout is exceeded.