Fuzzy Classification on Relational Databases

Author(s):  
Andreas Meier ◽  
Günter Schindler ◽  
Nicolas Werro

In practice, information systems are based on very large data collections mostly stored in relational databases. As a result of information overload, it has become increasingly difficult to analyze huge amounts of data and to generate appropriate management decisions. Furthermore, data are often imprecise because they do not accurately represent the world or because they are themselves imperfect. For these reasons, a context model with fuzzy classes is proposed to extend relational database systems. More precisely, fuzzy classes and linguistic variables and terms, together with appropriate membership functions, are added to the database schema. The fuzzy classification query language (fCQL) allows the user to formulate unsharp queries that are then transformed into appropriate SQL statements using the fCQL toolkit so that no migration of the raw data is needed. In addition to the context model with fuzzy classes, fCQL and its implementation are presented here, illustrated by concrete examples.

Author(s):  
Kiryoong Kim ◽  
Dongkyu Kim ◽  
Jeuk Kim ◽  
Sang-uk Park ◽  
Ighoon Lee ◽  
...  

Electronic catalogs are electronic representations about products and services in the electronic commerce environment and require diverse and flexible schemas. Although relational database systems seem to be an obvious choice for their storage, traditional designs of relational schemas do not support electronic catalogs in the most effective ways. Therefore, new models for managing diverse and flexible schemas in relational databases are required for such systems. Proposed in this paper are several models for electronic catalogs using relational tables, and an experimental evaluation of their efficiency. The results of this study can be put to practical use and are, in fact, being applied in the design of a commercial software product.


2021 ◽  
Vol 19 ◽  
pp. 151-158
Author(s):  
Piotr Rymarski ◽  
Grzegorz Kozieł

Most of today's web applications run on relational database systems. Communication with them is possible through statements written in Structured Query Language (SQL). This paper presents the most popular relational database management systems and describes common ways to optimize SQL queries. Using the research environment based on fragment of the imdb.com database, implementing OracleDb, MySQL, Microsoft SQL Server and PostgreSQL engines, a number of test scenarios were performed. The aim was to check the performance changes of SQL queries resulting from syntax modication while maintaining the result, the impact of database organization, indexing and advanced mechanisms aimed at increasing the eciency of operations performed, delivered in the systems used. The tests were carried out using a proprietary application written in Java using the Hibernate framework.


2018 ◽  
Vol 8 ◽  
pp. 263-269
Author(s):  
Grzegorz Dziewit ◽  
Jakub Korczyński ◽  
Maria Skublewska-Paszkowska

Comparison of efficiency is not a trivial phenomenon because of disparities between different database systems. This paper presents a methodology of comparing relational database systems in respect of mean time of execution individual DML queries containing subqueries and conjunction of tables. The presented methodology can be additionally accommodated to studies of efficiency in a range of database system itself (study of queries executed directly in database engine). The described methodology allows to receive statement telling which database system is better in comparison to another in dependency of functionalities fulfilled by external application. In the article the analysis of mean time of execution individual DML queries was performed.Two research hypotheses have been put forward: "Microsoft SQL Server database system needs less time to execute INSERT and UPDATE queries than Oracle database" and "Oracle database system needs less time to execute DML queries with binary data than SQL Server"


Author(s):  
Hans-Peter Kriegel ◽  
Peer Kröger ◽  
Martin Pfeifle ◽  
Stefan Brecheisen ◽  
Marco Pötke ◽  
...  

Similarity search in database systems is becoming an increasingly important task in modern application domains such as multimedia, molecular biology, medical imaging, and many others. Especially for CAD (Computer-Aided Design), suitable similarity models and a clear representation of the results can help to reduce the cost of developing and producing new parts by maximizing the reuse of existing parts. In this chapter, we present different similarity models for voxelized CAD data based on space partitioning and data partitioning. Based on these similarity models, we introduce anindustrial prototype, called BOSS, which helps the user to get an overview over a set of CAD objects. BOSS allows the user to easily browse large data collections by graphically displaying the results of a hierarchical clustering algorithm. This representation is well suited for the evaluation of similarity models and to aid an industrial user searching for similar parts.


Author(s):  
Gábor Szárnyas ◽  
János Maginecz ◽  
Dániel Varró

The last decade brought considerable improvements in distributed storage and query technologies, known as NoSQL systems. These systems provide quick evaluation of simple retrieval operations and are able to answer certain complex queries in a scalable way, albeit not instantly. Providing scalability and quick response times at the same time for querying large data sets is still a challenging task. Evaluating complex graph queries is particularly difficult, as it requires lots of join, antijoin and filtering operations. This paper presents optimization techniques used in relational database systems and applies them on graph queries. We evaluate various query plans on multiple datasets and discuss the effect of different optimization techniques.


2009 ◽  
Vol 20 (4) ◽  
pp. 1-25 ◽  
Author(s):  
Anteneh Ayanso ◽  
Paulo B. Goes ◽  
Kumar Mehta

Finding efficient methods for supporting top-k relational queries has received significant attention in academic research. One of the approaches in the recent literature is query-mapping, in which top-k queries are mapped (translated) into equivalent range queries that relational database systems (RDBMSs) normally support. This approach combines the advantage of simplicity as well as practicality by avoiding the need for modifications to the query engine, or specialized data structures or indexing techniques to handle top-k queries separately. However, existing methods following this approach fall short of adequately modeling the problem environment and providing consistent results. In this article, the authors propose a cost-based range estimation model for the query-mapping approach. They provide a methodology for trading-off relevant query execution cost components and mapping a top-k query into a cost-optimal range query for efficient execution. Their experiments on real world and synthetic data sets show that the proposed strategy not only avoids the need to calibrate workloads on specific database contents, but also performs at least as well as prior methods.


2008 ◽  
pp. 3694-3699
Author(s):  
William Perrizo ◽  
Qiang Ding ◽  
Masum Serazi ◽  
Taufik Abidin ◽  
Baoying Wang

For several decades and especially with the preeminence of relational database systems, data is almost always formed into horizontal record structures and then processed vertically (vertical scans of files of horizontal records). This makes good sense when the requested result is a set of horizontal records. In knowledge discovery and data mining, however, researchers are typically interested in collective properties or predictions that can be expressed very briefly. Therefore, the approaches for scan-based processing of horizontal records are known to be inadequate for data mining in very large data repositories (Han & Kamber, 2001; Han, Pei, & Yin, 2000; Shafer, Agrawal, & Mehta, 1996).


Author(s):  
Yangjun Chen

It is a general opinion that relational database systems are inadequate for manipulating composite objects that arise in novel applications such as Web and document databases (Abiteboul, Cluet, Christophides, Milo, Moerkotte & Simon, 1997; Chen & Aberer, 1998, 1999; Mendelzon, Mihaila & Milo, 1997; Zhang, Naughton, Dewitt, Luo & Lohman, 2001), CAD/ CAM, CASE, office systems and software management. Especially, when recursive relationships are involved, it is cumbersome to handle them in relational databases, which sets current relational systems far behind the navigational ones (Kuno & Rundensteiner, 1998; Lee & Lee, 1998). To overcome this problem, a lot of interesting graph encoding methods have been developed to mitigate the difficulty to some extent. In this article, we give a brief description of some important methods, including analysis and comparison of their space and time complexities.


1992 ◽  
pp. 46-64
Author(s):  
Harihodin Selamat

Recent advances in Artificial Intelligence and Relational Database systems have contributed to the development of Logic Database systems. A lot of research in logic database have been encompassed on the query evaluation and optimization techniques. Very litde effort has been put to the development of the user's query system to facilitate the naive users interacting with the database. Currently, the form of query is based on the primitive logic form. Therefore, this project aims at developing a prototype natural query system to the logic database as a compromise between the primitive logic query and the natural language query systems. This paper describes a conceptual framework of the natural query system. The concept of predicate universal relation is introduced as an interface to bridge the natural query and the corresponding primitive logic query. The concept of data types is employed as a tool towards the construction of the predicate universal relation. We believe this is the first attempt towards a natural query system for logic database via a universal relation approach. Keywords: query interface, logic database, deductive database, universal relation, query processing, query language, natural query, first order logic, data types


2016 ◽  
Vol 4 (3) ◽  
pp. 22-37 ◽  
Author(s):  
Nayem Rahman

Scorecard-based measurement techniques are used by organizations to measure the performance of their business operations. A scorecard approach could be applied to a database system to measure performance of SQL (Structured Query Language) being executed and the extent of resources being used by SQL. In a large data warehouse, thousands of jobs run daily via batch cycles to refresh different subject areas. Simultaneously, thousands of queries by business intelligence tools and ad-hoc queries are being executed twenty-four by seven. There needs to be a controlling mechanism to make sure these batch jobs and queries are efficient and do not consume database systems resources more than optimal. The authors propose measurement of SQL query performance via a scorecard tool. The motivation behind using a scorecard tool is to make sure that the resource consumption of SQL queries is predictable and the database system environment is stable. The experimental results show that queries that pass scorecard evaluation criteria tend to utilize optimal level of database systems computing resources. These queries also show improved parallel efficiency (PE) in using computing resources (CPU, I/O and spool space) that demonstrate the usefulness of SQL scorecard.


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