Structure of distributed database, Database Management System

Structure Of Distributed Database: A distributed database system haves of a collection of sites, each of which keeps a local databases system. Every site is able to process local transactions, the transactions that access data only in that one site. In addition, a site may participate in the implementation of global transactions, those transactions that access data at various sites.

The execution of global transactions on the distributed architecture needs communication between the sites. Figure illustrates a representative distributed database system architecture having transactions. Please note that both the transactions shown are global in nature as they need data from both the sites.

                    2207_Structure Of Distributed Database.png

                                   Figure: Distributed Database Schema and Transactions

   Some of the key issues including DDBMS are:

  • How the data is distributed?
  • Is this data distribution unseen from the general users?
  • How are the integration of data and its control including security managed globally and locally?
  • How are the distributed database related?

The sites in a distributed system can be related physically in a variety of ways. The several topologies are represented as graphs whose nodes correspond to sites. An edge from node A to node B communicates to a direct connection among the two sites.

Some of the most common connection structures are depicted in Figure. The main differences between these configurations involve:

  • Installation cost. The cost of physically connecting the sites in the system
  • Communication cost. The cost in time and money to send a message through site A to site B.
  • Reliability. The frequency with which a site or link fails.
  • Availability. The degree to which data can be accessed despite failure of some links or sites.

These differences play an vital role in choosing the appropriate mechanism for handling the distribution of data The sites of a distributed database system may be distributed physically either over a huge geographical area (such as all over India), or a small geographical area such as a one building or a number of adjacent buildings). The former type of network is based on broad area network, whereas the latter uses local-area network.

Posted Date: 3/12/2013 5:50:51 AM | Location : United States







Related Discussions:- Structure of distributed database, Assignment Help, Ask Question on Structure of distributed database, Get Answer, Expert's Help, Structure of distributed database Discussions

Write discussion on Structure of distributed database
Your posts are moderated
Related Questions
Assignment #1 Data Management The questions on this exam are based on the Baxter Aviation case scenario. 1. (5 points) The systems analyst proposes the following two relationshi

what is the need of a log in dbms

Probelm: a) In the context of OODBMS, define the following terms with appropriate examples. (i) Object class. (ii) Abstract class. (iii) Aggregation. (iv)

How can you terminate the MySQL Server? Typing the following in Command prompt will shut down the server completely as root user % mysqladmin -u root -p shutdown

Define instance and schema?  Instance:  Collection of  data  kept in the  data  base  at  a  particular  moment  is  known as an Instance of the database.  Schema: The o

What is abstraction? Abstraction in the object orientation is a idea that provide opportunity to express necessary properties of object without providing much details of the im

Explain weak and strong entity type ? Weak and Strong entity type: An entity set which does not have a primary key is referred to as a weak entity set. The existence of a wea

Command Line Interfaces: These are interactive interfaces, character-based that let you use the complete power and functionality of the DBMS query language directly. They permit yo

Assume that you are responsible for selecting a new DBMS product for Sohar Hospital

What are the three classes of SQL expression? SQL expression consists of three clauses:  Select  From  Where