Search results for "database."

Errors and Complications in SQL Query Formulation

2018

SQL is taught in almost all university level database courses, yet SQL has received relatively little attention in educational research. In this study, we present a database management system independent categorization of SQL query errors that students make in an introductory database course. We base the categorization on previous literature, present a class of logical errors that has not been studied in detail, and review and complement these findings by analyzing over 33,000 SQL queries submitted by students. Our analysis verifies error findings presented in previous literature and reveals new types of errors, namely logical errors recurring in similar manners among different students. We…

Distributed Coverage of Ego Networks in F2F Online Social Networks

2016

Although most online social networks rely on a centralized infrastructure, several proposals of Distributed Online Social Networks (DOSNs) have been recently presented. Since in DOSNs user profiles are stored on the peers of the users belonging to the network, one of the main challenges comes from guaranteeing the profile availability when the owner of the data is not online. In this paper, we propose a DOSN based on a friend-to-friend P2P overlay where the user's data is stored only on friend peers. Our approach is based on the ego-network concept, which models the social network from the local point of view of a single user. We propose a distributed algorithm which is based on the notion …

Contributions from ADBIS 2018 workshops

2018

The ADBIS conferences provide an international forum for the presentation of research on database theory, development of advanced DBMS technologies, and their applications. The 22nd edition of ADBIS, held on September 2–5, 2018, in Budapest, Hungary, includes six thematic workshops collecting contributions from various domains representing new trends in the broad research areas of databases and information systems.

Schema-Based Visual Queries over Linked Data Endpoints

2019

We present the option to use the schema-based visual query tool ViziQuer over realistic Linked Data endpoints. We describe the tool meta-schema structure and the means for the endpoint schema retrieval both from an OWL ontology and from a SPARQL endpoint. We report on a store of the endpoint-specific schemas and the options to support the schema presentation to the end-user both as a class tree within the environment and as external visual diagram.

Export of Relational Databases to RDF Databases: A Case Study

2010

The vast amount of business information nowadays is stored in relational databases. For the Semantic Web vision to become a reality, we need ways how to exploit this data in form of RDF triples. The universal and commonly accepted solution for this problem still does not exist. In most cases, mapping languages are used for specification of correspondences between OWL ontology and DB schema. At the same time, these languages generally are not well suited for specification of mappings in cases when there is a substantial difference between OWL ontology and DB schema. In this paper, we describe a new model transformation-based method for specification of correspondences between the elements of…

Databases and Information Systems

2001

A systematic analysis of duplicate records in Scopus

2015

In recent years, the Web of Science Core Collection and Scopus databases have become primary sources for conducting studies that evaluate scientific investigations. Such studies require that duplicate records be excluded to avoid errors of overrepresentation. In this line, we identify duplicate records in Scopus and examine their origins. Identifying journals with duplicate records in Scopus, selecting and downloading bibliographic journal records, and identifying and analyzing the duplicate records is the methodology adopted. Duplicate records are found when articles published in a journal are incorrectly mapped by Scopus to this journal and to a different journal from the same publisher a…

Wordnet and semidiscrete decomposition for sub-symbolic representation of words

2009

A methodology for sub-symbolic semantic encoding of words is presented. The methodology uses the standard, semantically highly-structured WordNet lexical database and the SemiDiscrete matrix Decomposition to obtain a vector representation with low memory requirements in a semantic n-space. The application of the proposed algorithm over all the WordNet words would lead to a useful tool for the sub-symbolic processing of texts.

Publish By Example

2008

We propose an approach for producing database publishing programs by example. The main idea is to interactively build an example document, representative of the program output. The system infers from this document, without ambiguity, the publishing program. The end-user does not need to know a programming language, a query language or the database schema.

Heuristic Method to Improve Systematic Collection of Terminology

2016

In this paper, we propose an experimental tool for analysis and graphical representation of glossaries. The original heuristic algorithms and analysis methods incorporated into the tool appeared to be useful to improve the quality of the glossaries. The tool was used for analysis of ISTQB Standard Glossary of Terms Used in Software Testing. There are instances of problems found in ISTQB glossary related to its consistency, completeness, and correctness described in the paper.