scholarly journals Null Values Treatment in Distributed Databases

2002 ◽  
Vol 40 (1) ◽  
pp. 55-64
Author(s):  
Saran Akram Abd Al-Majeed
Keyword(s):  
Programming Languages ◽  
Relational Databases ◽  
Distributed Databases ◽  
Distributed Database ◽  
Database Management System ◽  
Data Sources ◽  
Relational Model ◽  
A Value ◽  
Null Values ◽  
Distributed Database System

There has been a great deal of discussion about null values in relational databases. The relational model was defined in 1969, and Nulls Was died in 1979. Unfortunately, there is not a generally agreeable solution for rull values problem. Null is a special marker which stands for a value undefined or unknown, which means thut ne entry has been made, a missing valuc mark is not a value and not of a date type and cannot be treated as a value by Database Management System (DBMS). As we know, distributed database users are more than a single database and data will be distributed among several data sources or sites, it must be precise data, the replication is allowed there, so complex problems will appear, then there will be need for perfect practical general approaches for treatment of Nulls. A distributed database system is designed, that is "Hotel reservation control system, based on different data sources at four site, each site is represented as a Hotel, for more heterogeneity different application programming languages there are five practical approaches, designed with their rules and algorithms for Null values treatment through the distributed database sites. (1), (2), (3). 14). 15), (9).

MULTI-KEY INDEX FOR DISTRIBUTED DATABASE SYSTEM

2005 ◽  
Vol 15 (02) ◽  
pp. 433-438
Author(s):  
MD. SHAZZAD HOSAIN ◽  
MUHAMMAD ABDUL HAKIM NEWTON
Keyword(s):  
Distributed Databases ◽  
Database Systems ◽  
Distributed Database ◽  
Index Model ◽  
Network Bandwidth ◽  
Distributed Database Systems ◽  
Efficient Access ◽  
Distributed Database System ◽  
Bit Vector ◽  
Centralized Database

In this paper we present a multi-key index model that enables us to search a record with more than one attribute values in distributed database systems. Indices provide fast and efficient access of data and so become a major aspect in centralized database systems. Most of the centralized database systems use B + tree or other types of index structures such as bit vector, graph structure, grid file etc. But in distributed database systems no index model is found in the literature. Therefore efficient access is a major problem in distributed databases. Our proposed index model avoids the query-flooding problem of existing system and thus optimizes network bandwidth.

Distributed database system of the New Atlas of Amphibians and Reptiles in Europe: the NA2RE project

2014 ◽  
Vol 35 (1) ◽  
pp. 33-39 ◽  
Author(s):  
Neftalí Sillero ◽  
Marco Amaro Oliveira ◽  
Pedro Sousa ◽  
Fátima Sousa ◽  
Luís Gonçalves-Seco
Keyword(s):  
Spatial Data ◽  
Distributed Databases ◽  
Species Conservation ◽  
Distributed Database ◽  
Database System ◽  
Data Systems ◽  
Web Interface ◽  
Data Infrastructure ◽  
Societas Europaea ◽  
Distributed Database System

The Societas Europaea Herpetologica (SEH) decided in 2006 through its Mapping Committee to implement the New Atlas of Amphibians and Reptiles of Europe (NA2RE: http://na2re.ismai.pt) as a chorological database system. Initially designed to be a system of distributed databases, NA2RE quickly evolved to a Spatial Data Infrastructure, a system of geographically distributed systems. Each individual system has a national focus and is implemented in an online network, accessible through standard interfaces, thus allowing for interoperable communication and sharing of spatial-temporal data amongst one another. A Web interface facilitates the access of the user to all participating data systems as if it were one single virtual integrated data-source. Upon user request, the Web interface searches all distributed data-sources for the requested data, integrating the answers in an always updated and interactive map. This infrastructure implements methods for fast actualisation of national observation records, as well as for the use of a common taxonomy and systematics. Using this approach, data duplication is avoided, national systems are maintained in their own countries, and national organisations are responsible for their own data curation and management. The database could be built with different representation levels and resolution levels of data, and filtered according to species conservation matters. We present the first prototype of NA2RE, composed of the last data compilation performed by the SEH (Sillero et al., 2014). This system is implemented using only open source software: PostgreSQL database with PostGIS extension, Geoserver, and OpenLayers.

scholarly journals Implementasi Sistem Interkoneksi Basis Data Terdistribusi Menggunakan Socket API

2017 ◽  
Vol 1 (1) ◽  
pp. 1-4
Author(s):  
Ary Yulianto
Keyword(s):  
Information System ◽  
Big Data ◽  
Human Resources ◽  
Distributed Databases ◽  
Distributed Database ◽  
Database System ◽  
Master Data ◽  
Distributed Database System ◽  
The Moment ◽  
Asset Data

  Majelis Pendidikan Dasar dan Menengah Pimpinan Daerah Kabupaten Magelang needs information about the development of the school. The necessary data include data on human resources, asset data and data of their students. At the moment the data is obtained manually by looking to the schools. With the development of information technology is now expected to have a school information system that can provide information quickly and accurately. Data on each school if put into one large server or big data can be used to analyze the data. The purpose of this research is to implement the interconnection of distributed database system using the socket API. It is used to provide master data of all schools under Persyarikatan Muhammadiyah. To support the analysis of the data interconnection of distributed databases, socket API technology is used. With a system like this then the communications database can be connected so that the school's data will be sent directly through the socket API and the data will automatically be processed by the webservice in the server middleware and will be utilized in the next process.

scholarly journals Nonreplicated Static Data Allocation in Distributed Databases Using Biogeography-Based Optimization

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Arjan Singh ◽  
Karanjeet Singh Kahlon ◽  
Rajinder Singh Virk
Keyword(s):  
Data Transfer ◽  
Distributed Databases ◽  
Distributed Database ◽  
Database System ◽  
Data Allocation ◽  
Transmission Cost ◽  
Static Data ◽  
Total Data ◽  
Transfer Cost ◽  
Distributed Database System

Allocation of data is one of the key design issues of distributed database. A major cost of query execution in a distributed database system is the data transfer cost from one site to another site. The allocation of fragments among the different sites over the network plays an important role in performance of the distributed database system. The main objective of a data allocation in distributed database is to place the data fragments at different sites in such a way, so that the total data transfer cost can be minimized while executing a set of queries. In this paper, a new biogeography-based optimization (BBO) algorithm has been used to allocate the fragments during the design of distributed database system. The goal of this paper is to design a fragments allocation algorithm, so that the total data transmission cost can be minimized. To show the performance of proposed algorithm, results of biogeography-based optimization algorithm for data allocation are compared with genetic algorithm.

scholarly journals RESEARCH OF ACID TRANSACTION IMPLEMENTATION METHODS FOR DISTRIBUTED DATABASES USING REPLICATION TECHNOLOGY

2021 ◽  
pp. 19-31
Author(s):  
Oksana Mazurova ◽  
Artem Naboka ◽  
Mariya Shirokopetleva
Keyword(s):  
Relational Databases ◽  
System Analysis ◽  
Distributed Databases ◽  
Subject Area ◽  
Relational Model ◽  
Distributed Transactions ◽  
Business Operations ◽  
The Subject ◽  
Effective Use ◽  
Selection Of

Today, databases are an integral part of most modern applications designed to store large amounts of data and to request from many users. To solve business problems in such conditions, databases are scaled, often horizontally on several physical servers using replication technology. At the same time, many business operations require the implementation of transactional compliance with ACID properties. For relational databases that traditionally support ACID transactions, horizontal scaling is not always effective due to the limitations of the relational model itself. Therefore, there is an applied problem of efficient implementation of ACID transactions for horizontally distributed databases. The subject matter of the study is the methods of implementing ACID transactions in distributed databases, created by replication technology. The goal of the work is to increase the efficiency of ACID transaction implementation for horizontally distributed databases. The work is devoted to solving the following tasks: analysis and selection of the most relevant methods of implementation of distributed ACID transactions; planning and experimental research of methods for implementing ACID transactions by using of NoSQL DBMS MongoDB and NewSQL DBMS VoltDB as an example; measurements of metrics of productivity of use of these methods and formation of the recommendation concerning their effective use. The following methods are used: system analysis; relational databases design; methods for evaluating database performance. The following results were obtained: experimental measurements of the execution time of typical distributed transactions for the subject area of e-commerce, as well as measurements of the number of resources required for their execution; revealed trends in the performance of such transactions, formed recommendations for the methods studied. The obtained results allowed to make functions of dependence of the considered metrics on loading parameters. Conclusions: the strengths and weaknesses of the implementation of distributed ACID transactions using MongoDB and VoltDB were identified. Practical recommendations for the effective use of these systems for different types of applications, taking into account the resources consumed and the types of requests.

Organizing Multimedia Objects Using a Class Algebra Database

2002 ◽  
pp. 318-326 ◽  
Author(s):  
Daniel J. Buehrer
Keyword(s):  
Relational Databases ◽  
Web Search ◽  
Object Oriented ◽  
Distributed Database ◽  
Binary Relations ◽  
Traditional Use ◽  
Database Queries ◽  
Distributed Database System ◽  
The Many ◽  
Database Implementation

This chapter considers the question of how to locate appropriate multimedia objects. The traditional use of Web search engines is limited by the fact that there are as of yet no standard XML tags describing the many various types of multimedia objects. The users would much prefer to choose from menus, especially from a classification hierarchy where subclasses are all listed. Traditional SQL relational databases are generally not flexible enough to permit dynamic addition of attribute/value pairs to describe these multimedia objects, and to display the resulting schema. The solution suggested in this chapter is the sharing of class and binary relation definitions, including the binary superclass/subclass relation of the IS-A classification hierarchy of object-oriented technology. This object-oriented database implementation is based on class algebra. Similar users can see each other’s objects, classes, and relations, and add their own objects into appropriate places in both the class hierarchy and the binary relations. The binary relations look like subdirectories, and the available binary relations and methods can be chosen from a menu. The distributed database system, therefore, looks like a typical network operating system, and it is expected that average users may be able to make database queries and updates without any need of programmers.

scholarly journals Query Computation Time and Its Performance over Distributed Database Frameworks

2019 ◽  
Vol 8 (12) ◽  
pp. 5153-5160
Keyword(s):  
Data Privacy ◽  
Privacy Preservation ◽  
Clustering Algorithms ◽  
Distributed Databases ◽  
Computation Time ◽  
Distributed Database ◽  
Vital Role ◽  
Data Set ◽  
Security Issues ◽  
Distributed Database System

It is essential to maintain a relevant methodology for data fragmentation to employ resources, and thus, it needs to choose an accurate and efficient fragmentation methodology to improve authority of distributed database system. This leads the challenges on data reliability, stable storage space and costs, Communication costs, and security issues. In Distributed database framework, query computation and data privacy plays a vital role over portioned distributed databases such as vertical, horizontal and hybrid models, Privacy of any information is regarded as the essential issue in nowadays hence we show an approach by that we can use privacy preservation over the two parties which are actually distributing their data horizontally or vertically. In this chapter, I present an approach by which the concept of hierarchal clustering applied over the horizontally partitioned data set. We also explain the desired algorithm like hierarchal clustering, algorithms for finding the minimum closest cluster. Furthermore, it explores the performance of Query Computation over portioned databases with the analysis of Efficiency and Privacy.

scholarly journals Building a Retail Sysem Based on Distributed Databases Model

2019 ◽  
Vol 8 (10) ◽  
pp. 826-829
Keyword(s):  
Distributed System ◽  
Distributed Databases ◽  
Distributed Database ◽  
Database Management System ◽  
Entire System ◽  
Point Of Sale ◽  
Client Server ◽  
Processing Information ◽  
Important Field ◽  
Distributed Database Management

In recent years, distributed databases have become an important field of processing information, overcoming some limitations of centralized database such as overloading, bottlenecking while accessing, availability/ reliability of low fault tolerance. Our article proposes to build a distributed system (functions and databases) for POS (point of sale) retailers, data will be distributed across different locations but can still be linked together when required. At each location retailers can sell directly on the system (online or offline) so they can administer local databases and execute their local applications (business). Here we deploy the system on the distributed database management system based on Client-Server model. Therefore, aside from local management of data at clients (POS), there is also a server (manager) that stores data, manages and controls the entire system.

scholarly journals Research and implementation of HTAP for distributed database

2021 ◽  
Vol 39 (2) ◽  
pp. 430-438
Author(s):  
Changhong Jing ◽  
Wenjie Liu ◽  
Jintao Gao ◽  
Ouya Pei
Keyword(s):  
Data Analysis ◽  
Relational Databases ◽  
Distributed Databases ◽  
Distributed Database ◽  
Transaction Processing ◽  
Complex Data ◽  
Main Application ◽  
On Line ◽  
Analytical Processing ◽  
Implementation Method

Data processing can be roughly divided into two categories, online transaction processing OLTP(on-line transaction processing) and online analytical processing OLAP(on-line analytical processing). OLTP is the main application of traditional relational databases, and it is some basic daily transaction processing, such as bank pipeline transactions and so on. OLAP is the main application of the data warehouse system, it supports some more complex data analysis operations, focuses on decision support, and provides popular and intuitive analysis results. As the amount of data processed by enterprises continues to increase, distributed databases have gradually replaced stand-alone databases and become the mainstream of applications. However, the current business supported by distributed databases is mainly based on OLTP applications, lacking OLAP implementation. This paper proposes an implementation method of HTAP for distributed database CBase, which provides an implementation method of OLAP analysis for CBase, and can easily deal with data analysis of large amounts of data.

AN EFFICIENT TEST FOR THE VALIDITY OF UNBIASED HYBRID KNOWLEDGE FRAGMENTATION IN DISTRIBUTED DATABASES

1992 ◽  
Vol 02 (04) ◽  
pp. 589-609 ◽  
Author(s):  
YANCHUN ZHANG ◽  
MARIA E. ORLOWSKA ◽  
ROBERT COLOMB
Keyword(s):  
Relational Databases ◽  
Distributed Databases ◽  
Database Design ◽  
Database Systems ◽  
Distributed Database ◽  
Knowledge Bases ◽  
Global Database ◽  
Efficient Test ◽  
Global Schema ◽  
Hybrid Knowledge

Knowledge bases contain specific and general knowledge. In relational database systems, specific knowledge is often represented as a set of relations. The conventional methodologies for centralized database design can be applied to develop a normalized, redundancy-free global schema. Distributed database design involves redundancy removal as well as the distribution design which allows replicated data segments. Thus, distribution design can be viewed as a process on a normalized global schema which produces a collection of fragments of relations from a global database. Clearly, not every fragment of data can be permitted as a relation. In this paper, we clarify and formally discuss three kinds of fragmentations of relational databases, and characterize their features as valid designs, and we introduce a hybrid knowledge fragmentation as the general case. For completeness of presentation, we first show an algorithm for the validity test of vertical fragmentations of normalized relations, and then extend it to the more general case of unbiased fragmentations.

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