View update is an important mechanism that allows updates on a view by translating them into the corresponding updates on the base relations. The existing literature has shown the ambiguity of translating view updates. To address this ambiguity, we propose a robust language-based approach for making view update strategies programmable and validatable. Specifically, we introduce a novel approach to use Datalog to describe these update strategies. We propose a validation algorithm to check the well-behavedness of the written Datalog programs. We present a fragment of the Datalog language for which our validation is both sound and complete. This fragment not only has good properties in theory but is also useful for solving practical view updates. Furthermore, we develop an algorithm for optimizing user-written programs to efficiently implement updatable views in relational database management systems. We have implemented our proposed approach. The experimental results show that our framework is feasible and efficient in practice.

In relational database management systems, views are rarely automatically updatable because of the inherent ambiguity of view updates. To allow view updates, database administrators have to decide and implement an update strategy that must be well-behaved with the view definition to guarantee consistency between the view and the underlying database. In this demonstration, we explore the development process of such view update strategies with the assistance of our framework, called BIRDS. BIRDS enables users to specify view update strategies declaratively using Datalog. BIRDS validates the well-behavedness of user-written update strategies, then optimizes and compiles them into SQL code run in PostgreSQL databases. BIRDS further explains the unexpected behavior of user-written Datalog programs using generated counterexamples, thereby assists users in correcting their programs. We demonstrate all the steps in developing view update strategies via an easy to use interface provided by our system.