Concept

Conjunctive query

Related publications (26)

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Solid-State Storage and Work Sharing for Efficient Scaleup Data Analytics

Manoussos Gavriil Athanassoulis

Today, managing, storing and analyzing data continuously in order to gain additional insight is becoming commonplace. Data analytics engines have been traditionally optimized for read-only queries assuming that the main data reside on mechanical disks. The ...

EPFL2014

Incremental Query Evaluation in a Ring of Databases

Christoph Koch

This article approaches the incremental view maintenance problem from an algebraic perspective. The algebraic structure of a ring of databases is constructed and extended to form a powerful aggregate query calculus. The query calculus inherits the key prop ...

2013

Predictable performance and high query concurrency for data analytics

George Candea

Conventional data warehouses employ the query- at-a-time model, which maps each query to a distinct physical plan. When several queries execute concurrently, this model introduces contention and thrashing, because the physical plans—unaware of each other—c ...

2011

Incremental Query Evaluation in a Ring of Databases.

Christoph Koch

This paper approaches the incremental view maintenance problem from an algebraic perspective. We construct a ring of databases and use it as the foundation of the design of a query calculus that allows to express powerful aggregate queries. The query calcu ...

2010

Efficient Processing of Ranking Queries in Novel Applications

Parisa Haghani

Ranking queries, which return only a subset of results matching a user query, have been studied extensively in the past decade due to their importance in a wide range of applications. In this thesis, we study ranking queries in novel environments and setti ...

EPFL2010

On Probabilistic Fixpoint and Markov Chain Query Languages.

Christoph Koch

We study highly expressive query languages such as datalog, fixpoint, and while-languages on probabilistic databases. We generalize these languages such that computation steps (e.g. datalog rules) can fire probabilistically. We define two possible semantic ...

2010

Approximate Confidence Computation in Probabilistic Databases.

Christoph Koch

This paper introduces a deterministic approximation algorithm with error guarantees for computing the probability of propositional formulas over discrete random variables. The algorithm is based on an incremental compilation of formulas into decision diagr ...

2010

Generalized Hypertree Decompositions: NP-hardness and Tractable Variants

Zoltán Miklós

The generalized hypertree width GHW(H) of a hypergraph H is a measure of its cyclicity. Classes of conjunctive queries or constraint satisfaction problems whose associated hypergraphs have bounded GHW are known to be solvable in polynomial time. However, i ...

2009

A Scalable, Predictable Join Operator for Highly Concurrent Data Warehouses

George Candea

Conventional data warehouses employ the query-at-a-time model, which maps each query to a distinct physical plan. When several queries execute concurrently, this model introduces contention, because the physical plans—unaware of each other—compete for acce ...

2009

Contextualized and personalized location-based services

Shijun Yu

Advances in the technologies of smart mobile devices and tiny sensors together with the increase in the number of web resources open up a plethora of new mobile information services where people can acquire and disseminate information at any place and any ...

EPFL2008