In this chapter, we present an extensive study of database operations on mobile devices which provides an understanding and direction for processing data locally on mobile devices. Generally, it is not efficient to download everything from the remote databases and display on a small screen. Also in a mobile environment, where users move when issuing queries to the servers, location has become a crucial aspect. Our taxonomy of database operations on mobile devices mainly consists of on-mobile join operations and onmobile location dependent operations. For the on-mobile join operation, we include pre- and post-processing whereas for on-mobile location dependent operations, we focus on set operations arise from location-dependent queries.