Many declarative query languages for object-oriented databases allow nested subqueries.
This paper contains the first (to our knowledge) proposal to optimize them. A two-phase …

Sleep quality impacts virtually all aspects of life, including health, mood, emotions, cognition,
memory, behavior, and performance. Actigraphy offers a lower-cost alternative to …

Algebraic transformation and optimization techniques have been the method of choice in
relational query execution, but applying them in object-oriented (OO) DBMSs is difficult due …

Compilers and optimizers for declarative query languages use some form of intermediate
language to represent user-level queries. The advent of compositional query languages for …

We investigate the optimization and evaluation of queries with universal quantification in the
context of the object-oriented and object-relational data models. The queries are classified …

We present algebraic equivalences that allow to unnest nested algebraic expressions for
order-preserving algebraic operators. We illustrate how these equivalences can be applied …

Queries formulated in a nested way are very common in XQuery. Unfortunately, their
evaluation is usually very inefficient when done in a straightforward fashion. We present a …

There are no compelling reasons why database-internal query representations have to be
designated by operators. This thesis describes a world in which datatypes determine the …

With the substantial change of declarative query languages from plain SQL to the so-called
“object SQLs”, in particular OQL, there has surprisingly been not much change in the way …

This work tries to employ the monoid comprehension calculus-which has proven to be an
adequate framework to capture the semantics of modern object query languages featuring a …