Join ordering and join processing has a huge impact on query execution and can easily
affect the query response time by orders of magnitude. In particular, when joins are …

We present a dynamic index structure for join sampling. Built for an (equi-) join Q---let IN be
the total number of tuples in the input relations of Q---the structure uses~ O (IN) space …

We investigate the enumeration of top-k answers for conjunctive queries against relational
databases according to a given ranking function. The task is to design data structures and …

We study the enumeration of answers to ontology-mediated queries (OMQs) where the
ontology is a set of guarded TGDs or formulated in the description logic ELI and the query is …

Most data analytical pipelines often encounter the problem of querying inconsistent data that
violate pre-determined integrity constraints. Data cleaning is an extensively studied …

A Join-Project operation is a join operation followed by a duplicate eliminating projection
operation. It is used in a large variety of applications, including entity matching, set analytics …

In this paper, we investigate space-time tradeoffs for answering conjunctive queries with
access patterns (CQAPs). The goal is to create a space-efficient data structure in an initial …

Ciphertexts of an order-preserving encryption (OPE) scheme preserve the order of their
corresponding plaintexts. However, OPEs are vulnerable to inference attacks that exploit this …

This thesis offers two logic-based approaches to conjunctive queries in the context of
information extraction. The first and main approach is the introduction of conjunctive query …

Database queries can produce a huge output that is infeasible to compute, regardless of the
algorithm or system that processes them. This can often occur when the query joins large …