In recent years, there has been an explosion of interest in
data structures, which store the given data in compact or compressed formats and answer queries on the data rapidly while it is still in its compressed format. Our focus in this talk is to introduce
data structures. Encoding data structures consider the data together with the queries and aim to store only as much information about the data as is needed to store the queries. Once this is done, the original data can be deleted. In many cases, one can obtain space-efficient encoding data structures even when the original data is incompressible.