ACM Transactions on Database Systems

We study the question of when we can provide direct access to the k-th answer to a Conjunctive Query (CQ) according to a specified order over the answers in time logarithmic in the size of the database, following a preprocessing step that constructs a ...

Sorting and searching are large parts of database query processing, e.g., in the forms of index creation, index maintenance, and index lookup, and comparing pairs of keys is a substantial part of the effort in sorting and searching. We have worked on ...

Event data are often dirty owing to various recording conventions or simply system errors. These errors may cause serious damage to real applications, such as inaccurate provenance answers, poor profiling results, or concealing interesting patterns from ...