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About 10,000 papers for “database queries”

Undeniable Database Queries

Ahto Buldas Akadeemia, Ahto Buldas, Meelis Roos et al. · 2002

Let D be a public on-line database that is maintained by a party who is possibly not completely trustworthy. We study cryptographic techniques preventing the party (1) from undetectably modifying the content of D, and (2) from giving contradictory answers to the same query q, after a relatively short cryptographic digest d of D is made public. Previous work by Buldas, Laud and Lipmaa gives efficient solution for queries that require the answer Yes or No. The goal of this paper is to widen the scope of their techniques and cover much more complex types of queries. We present efficient methods for the queries that return a list of consecutive records as the reply. We show that the amount of additional cryptographic code that must be included into the answer can still remain quite small.

Cited by 0

Practical Database Queries

Apress eBooks · 2008

The last several chapters served as an introduction to numerous concepts regarding using PHP and MySQL together to retrieve and manipulate data. This chapter expands your knowledge, demonstrating several challenges that you’re bound to repeatedly encounter while creating database-driven Web applications. In particular, you’ll learn more about the following concepts: Tabular output: Listing query results in an easily readable format is one of the most commonplace tasks you’ll implement when building database-driven applications. This chapter explains how to programmatically create these listings, and how to extend the mysqli interface to incorporate new custom functionality. Sorting tabular output: Often, query results are ordered in a default fashion, by product name, for example. But what if the user would like to reorder the results using some other criteria, such as price? You’ll learn how to provide table-sorting mechanisms that let the user search on any column. Subqueries: Even simple data-driven applications often require queries to work with multiple tables, typically using joins. However, as you’ll learn, many of these operations can also be accomplished with the arguably much more intuitive subquery, available as of MySQL 4.1. Cursors: Very similar to how an array pointer enables you to easily navigate throughout an array’s elements, a cursor (a feature new to MySQL 5.0) enables you to swiftly navigate database result sets, as described later in this chapter. Paged results: Database tables often consist of hundreds, even thousands, of records. When large result sets are retrieved, it often makes sense to separate these results across several pages and provide the user with a mechanism to navigate back and forth between these pages. This chapter explains how to do so.

Cited by 0

Database Queries as. . .

Shuichi Miyazaki · 1996

this paper, we do challenge this combinatorial optimization over databases whose structure may be complicated but whose size is moderate. The obvious approach, i.e., to develop a specific algorithm for each optimization problem, does not seem to work: First of all it is not easy to develop such algorithms as described above and even if it would be possible, we could not expect sufficient performances. Instead, we develop an algorithm that translates the optimization problem into the CNF Satisfiability problem (SAT). The optimization problem can be regarded as a problem that requires constructing a new relation T from the given database, i.e., a set of relations. Regardless of how to solve it, our first step would be to write down formal conditions T should satisfy. Roughly speaking, the translation is nothing more than this step; its algorithm is fairly straightforward. We can expect several advantages: (i) As mentioned above, designing translation algorithms is much easier than designing solving algorithms. Translation algorithms usually run quickly. (ii) To solve the translated problem, i.e., the satisfiability of CNF formulas, we can use existing SAT algorithms whose recent development is most remarkable (see the next section) . (iii) The notion of approximation, which has also gained a great progress recently in the field of discrete algorithms[e.g., GW94], can be used naturally. Approximation is already a built-in facility in many SAT algorithms. This last feature might be the most important in practice. Of course there are concerns also. The most serious one is the efficiency of the translation. We cannot deny the fact that translating one problem into another suffers from several overheads. However, it is also a fact that we can take advantage of highly-tuned S...

Cited by 0

Practical Database Queries

Frank M. Kromann · Apress eBooks · 2018

The last several chapters served as an introduction to numerous concepts regarding using PHP and MySQL together to retrieve and manipulate data. This chapter expands your knowledge, demonstrating several challenges that you’re bound to repeatedly encounter while creating database-driven web applications. In particular, you’ll learn more about the following concepts:

Cited by 0

Database search queries.

Sara Dada (8117609), Henry Ashworth (10960534), Alina Sobitschka (10960537) et al. · Figshare · 2021

Cited by 0Open access

Visual database queries temporal.

Gilene Fernandes. SANTOS · LA Referencia (Red Federada de Repositorios Institucionales de Publicaciones Científicas) · 2000

O ambiente visual de consulta temporal, denominado TVQE (Temporal Visual Environment Query – TVQE), permite a formulação de consultas a banco de dados históricos. Este ambiente adota uma representação diagramática do esquema conceitual do banco de dados (incluindo classes e relacionamentos, temporais ou não) e uma “agenda gráfica” como metáfora de interação. O usuário pode formular tanto consultas convencionais como temporais, sendo que, para consultas temporais o ambiente oferece uma interação específica com operadores especiais utilizados para construção das condições temporais. Nesta dissertação, foram realizadas modificações e extensões no TVQE, além de um componente denominado Tradutor, que transforma as consultas formuladas pelo usuário no TVQE para SQL. As modificações realizadas estão relacionadas aos aspectos de interação do sistema com o usuário, tais como: a inclusão de um painel de mensagens e a sincronização de componentes gráficos (menus, ícones e painéis). As extensões realizadas foram: a formulação de consultas complexas como um novo tipo de consulta, a visualização do esquema gráfico do resultado da consulta e a migração do ambiente TVQE para um applet Java.

Cited by 0Open access

Undeniable Replies For Database Queries

Ahto Buldas, Meelis Roos, Jan Willemson et al. · 2002

Let D be a public on-line database that is maintained by a party who is possibly not completely trustworthy. We study cryptographic techniques preventing the party (1) from undetectably modifying the content of D, and (2) from giving contradictory answers to the same query q, after a relatively short cryptographic digest d of D is made public. Previous work by Buldas, Laud and Lipmaa gives efficient solution for queries that require the answer Yes or No. The goal of this paper is to widen the scope of their techniques and cover much more complex types of queries. We present efficient methods for the queries that return a list of consecutive records as the reply. We show that the amount of additional cryptographic code that must be included into the answer can still remain quite small.

Cited by 0

Database Interrogation Using Conjunctive Queries

Micha Bielecki Warsaw, Micha L Bielecki, Jan Van Den Bussche · 2007

We consider a scenario where a client communicates with a database server by posing boolean conjunctive queries, or more generally, counts of conjunctive queries. We investigate to what extent features such as quanti cation, negation, or non-equalities are important in such a setting.

Cited by 0

Transformation of TCP-Net Queries into Preference Database Queries

2008

Abstract. TCP-nets are a popular approach within the AI community for preference handling. Concurrently, within the database community lots of work has been done to integrate preference handling into database query languages like Preference SQL, building on a variety of preference constructors under a strict partial order semantics. Moreover, many sophisticated algebraic optimization techniques and preference query evaluation algorithms have been developed there. This paper attempts to build a bridge between these two disciplines. We show how to systematically transform TCPnet queries into database preference queries, introducing a special ceteris-paribus embedding preference constructor. Moreover, this transformation opens up options to enhance the expressiveness of TCP-nets. On the other hand, it forms a basis for future studies of advanced TCP-net optimization techniques that can benefit from known results for preference query optimization in database systems. 1

Cited by 0

Insert queries in XML database

P. Vidhya, Philip Samuel · 2010

The need for interoperation and data exchange through the Internet has made Extensible Markup Language (XML) a dominant standard for data representation, while relational databases are widely used in enterprises to support critical business operations. XML querying language (XUpdate) is used to modify XML documents where as structured query language (SQL) for retrieving and manipulating data in relational databases. It may not be possible for users and developers to be familiar with both the query languages easily and quickly. Here, we examine how XML data can be modified using INSERT and UPDATE. In this paper, we propose a new concept and framework where SQL (INSERT, UPDATE) can be easily transformed to XUpdate expressions. We use SQL, as it has long been the standard language. Users can manipulate XML database through the query language SQL using our framework. We present algorithms for translating INSERT and UPDATE queries expressed in SQL to XUpdate and the experimental results validate the proposed approach.

Cited by 3

Spatiotemporal Queries in Database Systems

Position Paper For, Carlo Zaniolo · 2007

systems. Indeed, the ine#ectiveness of state-of-the-art Object Relational Systems in supporting data mining applications is well-documented [4]. This dismal situation calls for a critical reevaluation of current approaches, objectives, and assumptions. In my view, the best that can be realistically expected, for the short term or mediumterm, is database systems supporting data models and query languages that are significantly more powerful and extensible than the current ones. These improved database systems will provide domain scientists with better tools and more flexible database environments to write complex spatio-temporal queries, and data-intensive applications. (Examples of some concrete steps in this direction are discussed below.) 1 In my view, however, domain scientists cannot reasonably hope for built-in spatiotemporal data models and query languages that will provide ready-made solutions for organizing and querying their scientific data. The complexity and diversity of

Cited by 0

Dynamic prioritization of database queries

Sivaramakrishnan Narayanan, Florian Waas · 2011

Enterprise database systems handle a variety of diverse query workloads that are of different importance to the business. For example, periodic reporting queries are usually mission critical whereas ad-hoc queries by analysts tend to be less crucial. It is desirable to enable database administrators to express (and modify) the importance of queries at a simple and intuitive level. The mechanism used to enforce these priorities must be robust, adaptive and efficient. In this paper, we present a mechanism that continuously determines and re-computes the ideal target velocity of concurrent database processes based on their run-time statistics to achieve this prioritization. In this scheme, every process autonomously adjusts its resource consumption using basic control theory principles. The self-regulating and decentralized design of the system enables effective prioritization even in the presence of exceptional situations, including software defects or unexpected/unplanned query termination with no measurable overhead. We have implemented this approach in Greenplum Parallel Database and demonstrate its effectiveness and general applicability in a series of experiments.

Cited by 13

Ranked Enumeration for Database Queries

Nikolaos Tziavelis, Wolfgang Gatterbauer, Mirek Riedewald · arXiv (Cornell University) · 2024

Ranked enumeration is a query-answering paradigm where the query answers are returned incrementally in order of importance (instead of returning all answers at once). Importance is defined by a ranking function that can be specific to the application, but typically involves either a lexicographic order (e.g., "ORDER BY R.A, S.B" in SQL) or a weighted sum of attributes (e.g., "ORDER BY 3*R.A + 2*S.B"). Recent work has introduced any-k algorithms for (multi-way) join queries, which push ranking into joins and avoid materializing intermediate results until necessary. The top-ranked answers are returned asymptotically faster than the common join-then-rank approach of database systems, resulting in orders-of-magnitude speedup in practice. In addition to their practical usefulness, these techniques complement a long line of theoretical research on unranked enumeration, where answers are also returned incrementally, but with no explicit ordering requirement. For a broad class of ranking functions with certain monotonicity properties, including lexicographic orders and sum-based rankings, the ordering requirement surprisingly does not increase the asymptotic time or space complexity, apart from logarithmic factors. A key insight is the connection between ranked enumeration for database queries and the fundamental task of computing the kth-shortest path in a graph. Although this connection is important for grounding the problem in the literature, it can obfuscate the simplicity of the algorithm. In this article, we adopt a pragmatic approach and present a slightly simplified version of the algorithm without the shortest-path interpretation. We believe that this will benefit practitioners looking to implement and optimize any-k approaches.

Cited by 0Open access

Scoping monadic relational database queries

Anton Ekblad · 2019

We present a novel method for ensuring that relational database queries in monadic embedded languages are well-scoped, even in the presence of arbitrarily nested joins and aggregates. Demonstrating our method, we present a simplified version of Selda, a monadic relational database query language embedded in Haskell, with full support for nested inner queries. To our knowledge, Selda is the first relational database query language to support fully general inner queries using a monadic interface.

Cited by 0