This book constitutes the refereed proceedings of the Second International Workshop on Datalog 2.0, held in Vienna, Austria, in September 2012. The 14 revised full papers presented together with 2 invited talks and 2 invited tutorials were carefully reviewed and selected from 17 initial submissions. Datalog 2.0 is a workshop for Datalog pioneers, implementors, and current practitioners; the contributions aim to bring every participant up-to-date with the newest developments and map out directions for the future.