sometime we don't have keys to fetch the data, i was wondering what is the best approach to fetch the data using values, also wondering if there is any plans for query support like http://docs.oracle.com/cd/E15357_01/coh.360/e15723/api_cq.htm and indexing in the future.
Only keys may be used to fetch values, however, you can use a key prefix (parent key), sub-key range, and depth. By designing your keys with this in mind, you can sometimes avoid the need for indexing.
It is also possible to create keys and values that work essentially as an index, by having one kv pair refer to another key via information in the value portion. But it is currently the application's responsibility to implement this -- to store all such associated kv pairs the and fetch the referenced kv pairs using multiple queries -- since there is no explicit support for it in the product.
On future features, I'm afraid that as an Oracle employee I can't discuss them, sorry.