PROJECT TITLE :

On the Complexity of Bounded View Propagation for Conjunctive Queries - 2018

ABSTRACT:

The read propagation problem is a class of read update downside in relational databases [7], involving deletion and insertion propagations. Given source database D, conjunctive question Q, read V generated by query Q(D) and a deletion (insertion) on read ?V, deletion (insertion) propagation is to seek out a aspect effect free update ?D on D such that the deletion (insertion) of ?D from (into) D can delete (insert) the intentional ones ?V without ensuing in the deletion (insertion) of extra tuples from (into) the view. Usually, such a deletion (insertion) is aspect result free. The related information management applications embody question result rationalization, data debugging, and anonymizing datasets, which depend on understanding how interventions in a database have an effect on the output of a question. Read propagation may be a natural and typical means to outline such interventions, which looks to be well-studied. But, generally, the candidate update on a source database is picked up aimlessly earlier, making the updated database to be terribly distant from the original one irrespective of whether it's the utmost one. During this Project, we have a tendency to formally outline the bounded view propagation drawback, where candidate update ?D is bounded as a subset of potential C that could be a fastened small tuple set of D. We tend to study the complexity of this drawback for conjunctive queries, and make contributions to the previous results of the issues of aspect-impact free deletion propagation. Specifically, our bounded read propagation downside decreases computational complexity no matter conjunctive question structure. We tend to show the fixed potential is actually a dichotomy for both deletion and insertion propagations, and determine the results on combined complexity that is neglected previously. Based mostly on our results, for read propagation, we have a tendency to map out a complete picture of the computational complexity hierarchy for conjunctive queries on each knowledge and combined complexities. Moreover, this bounded version is an update forbidden case of read propagation, and our results can be applied to it.