  This paper addresses the Data-Diff problem: given a dataset and a subsequent
version of the dataset, find the shortest sequence of operations that
transforms the dataset to the subsequent version, under a restricted family of
operations. We consider operations similar to SQL UPDATE, each with a condition
(WHERE) that matches a subset of tuples and a modifier (SET) that makes changes
to those matched tuples. We characterize the problem based on different
constraints on the attributes and the allowed conditions and modifiers,
providing complexity classification and algorithms in each case.
