Failures and recovery, Database Management System

Assignment Help:

Failures and Recovery

In practice various things might occur to prevent a transaction from completing. Recovery methods are used to bring database, which does not satisfy consistency needs, into a consistent state.  If a transaction finishes normally and commits then all the alters made by the transaction on the database are permanently registered in the database. They should not be lost. But, if a transaction does not finish normally and terminates abnormally then all the changes made by it should be discarded.  An abnormal termination of a transaction may be because of various causes, including:

a)  User may decide to terminate the transaction issued by him/ her

 b)  There may be a deadlock in the system

c)   There may be a system failure.

The recovery mechanisms must make sure that a consistent state of database can be restored under all circumstances.  In case of transaction terminate or deadlock, the system remains in control and can deal with the failure but in case of a system failure the system loses control because the computer itself has failed. Will the results of such type of failure be catastrophic? A database has a vast amount of useful information and any system failure should be recognised on the restart of the system. The DBMS should recover from some such failures.

 


Related Discussions:- Failures and recovery

Normalization, Process of normalization is the integral part of designing a...

Process of normalization is the integral part of designing a database. Justify this statement with suitable database design

Graphical user interface tools, These are interactive interfaces, graphical...

These are interactive interfaces, graphical that hide the difficulty of the DBMS and query language behind an intuitive, simple to understand, and convenient interface. This permit

What are the several forms of identity, What are the several forms of ident...

What are the several forms of identity? a) Value b) Name c) Built-in

What is data defination language, What is DDL? Make a list of commands with...

What is DDL? Make a list of commands with short description used in DDL Ans: Data Definition Language that is abbreviated as DDL is a computer language for defining data struct

Analyzing association traversal, Analyzing Association Traversal Assoc...

Analyzing Association Traversal Association Traversal shall be understood properly for the association design explanation.  Analyzing association traversal means analyzing tra

Data base model, why are older data base model are being replaced by new da...

why are older data base model are being replaced by new data model

Construct substantial data model, PART MARKING:  We will only mark TWO of t...

PART MARKING:  We will only mark TWO of the four questions below but you must submit answers to all four. We will choose the questions we mark randomly and we will supply you with

Define seek time, Define seek time. The time for repositioning the arm ...

Define seek time. The time for repositioning the arm is known as the seek time and it enhances with the distance that the arm is known as the seek time.

What are the dbms languages, What are the DBMS languages? Explain.  Ans...

What are the DBMS languages? Explain.  Ans: a) Data Definition Languages (DDL): It is employed to specify database schema for example CREATE DROP statements etc.     b)  Dat

Explain cascade and restrict clauses of drop schema command, Explain severa...

Explain several types of constraints that can be specified using CREATE TABLE command. Explain CASCADE and RESTRICT clauses of DROP SCHEMA command? Constraint Description PRIM

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd