Fragmentasi

ACM Transactions on Database Systems, 1991

Data fragmentation is an important aspect of distributed database design, in which portions of relations, tailored to the specific needs of local applications, are defined to be further allocated to the sites of the computer network supporting the database system. In this paper we present a theory of fragmentation with overlapping fragments to study the complexity of the problems involved in checking the completeness of a fragmentation schema and in querying and updating a fragmented relation. We analyze these problems from the complexity viewpoint and present sound and complete algorithms for their solution.

Proceedings of the VLDB Endowment, 2010

We propose a modeling of the problem of privacy-compliant data publishing that captures confidentiality constraints on one side and visibility requirements on the other side. Confidentiality constraints express the fact that some attributes, or associations among them, are sensitive and cannot be released. Visibility requirements express requests for views over data that should be provided. We propose a solution based on data fragmentation to split sensitive associations while ensuring visibility. In addition, we show how sensitive associations broken by fragmentation can be released in a sanitized form as loose associations formed in a way to guarantee a specified degree of privacy.

We deene mixed fragmentation as a process of simultaneously applying the horizontal and vertical fragmentation on a relation. It can be achieved in one of two ways: by performing horizontal fragmentation followed by vertical fragmentation or by performing vertical fragmentation followed by horizontal fragmentation. The need for mixed fragmentation arises in distributed databases because database users usually access subsets of data which are vertical and horizontal fragments of global relations and there is a need to process queries or transactions that would access these fragments optimally. We present algorithms for generating candidate vertical and horizontal fragmentation schemes and propose a methodology for distributed database design using these fragmentation schemes. When applied together these schemes form a grid. This grid consisting of cells is then merged to form mixed fragments so as to minimize the number of disk accesses required to process the distributed transactions. We have implemented the vertical and horizontal fragmentation algorithms and are developing a Distributed Database Design Tool to support the proposed methodology.

Conference Proceedings of the 2000 IEEE International Performance, Computing, and Communications Conference (Cat. No.00CH37086)

Fragmentology #6, 2023

Fragmentology is an international, peer-reviewed Open Access journal, dedicated to publishing scholarly articles and reviews concerning medieval manuscript fragments.

The Wiley-Blackwell Encyclopedia of Globalization, 2012

Fragmentology 3 (2020), 2020

A Journal for the Study of Medieval Manuscript Fragments Fragmentology is an international, peer-reviewed Open Access journal, dedicated to publishing scholarly articles and reviews concerning medieval manuscript fragments.

Various companies and establishments today are using distributed database system for daily business transactions in different domains. Some critical issues have been observed related to the complexity, maintenance, performance and communication cost of data in distributed data repository for query processing, according to the demand of end users from different locations. Distributed database helps to allocate data as fragmented, replicated and distributed over the intranet or Internet within and across an organization. In this paper, we developed an efficient model for fragment allocation in a distributed database system. These algorithms-genetic, clustering and fragmentation-were employed in allocating database fragments to individual sites and collating these distributed databases to one central store. Object oriented analysis and design methodology (OOADM) was employed in the systematic study and design of the system. Create, read, update and delete (CRUD) techniques, Bootstrap, cascading Style Sheet (CSS) and JavaScript were employed in the implementation of the system. MongoDB database engine was used to implement the database of the system. The result is a system with external fragmented database with capability of saving to a central database. This system can be used for every individual, organizations and establishments that has need to fragment database in a distributed database system for a maximum reduction of process time, for easy access of data and for complexity reduction. INTRODUCTION The increasing complexity of information and communication technology (ICT) development in all facets of life, including the field of computer science has necessitated the urgent need for developing a model for fragment allocation in a distributed database system. The concern for this has shown a distributed database system as being imperative in achieving better efficiency and easy retrieval of information in establishments; this is particularly observable in the banking system in Nigeria. It is a known fact that every establishment has its own peculiar database, but there appears to be a necessity to develop an efficient model for fragment allocation in a distributed database system in order to be in tandem with the international best practices. Allocation is the process of assigning a function or an activity to a database. In today's financial institutions, most banks have their own database system but still need to be collated and run a fragmented central system for all banks irrespective of banking type or name. There is need for fragmentation because in a distributed database the cumbersomeness of use of data, the difficulty in accessing and manipulating data, reduction of performance speeds in accessing and the problem in data retrieval. An efficient model was developed for allocating fragments that are in a distributed database systems to one database using two techniques which are clustering technique and Genetic technique. Genetic technique comes into play as to identify the activities which are to be clustered. In order words, there are so many activities performed by banks in Nigeria but this work is limited to only transactions (credit and debit of account), and also payment of utility bills. These techniques came into use by first of all clustering the number of banks that will be in use in order to achieve this work, after which activities which the banks will perform are also clustered. Genetic technique comes into play as to identify the activities which are to be clustered. There is difficulty in accessing and manipulation of data in a distributed database, reduction of performance speed in accessing a distributed database and distributed database poses a problem in data retrieval, as such, introduction of fragmentation is very pertinent.

Proceeding of the 2007 …, 2007

Fragmentation and allocation are database distribution design techniques used to improve the system performance by increasing data localisation and reducing data transportation costs between different network sites. Often fragmentation and allocation are considered separately, ...

Fragmentology, 2018

Fragmentology is an international, peer-reviewed Open Access journal, dedicated to publishing scholarly articles and reviews concerning medieval manuscript fragments.