Dirty reads-problems of concurrent transactions, Database Management System

Assignment Help:

Dirty Reads: T10 reads a value which is updated by T9. This update has not been committed and T9 aborts.

T9	T10	Value of x old value = 200
T9	T10	T9	T10
UPDATE X		500
	READ X		500
ROLLBACK		200	?

Here T10 reads a value that is updated by transaction T9 that has been aborted. Therefore T10 has read a value that would never exist in the database and hence the trouble. Here the difficulty is primarily of isolation of transaction.

Related Discussions:- Dirty reads-problems of concurrent transactions

Explain the reason for keeping legacy system, In order to keep pace with co...

In order to keep pace with competitors, Space Ltd has decided to implement an ERP system in order to replace its old legacy and manual systems. Management does not have much knowle

Normalization, in case of functional dependencies how we get the higher nor...

in case of functional dependencies how we get the higher normal form.

What are ways of finding out derived attributes, What are ways of finding o...

What are ways of finding out either an update is required or not for derived attributes? The ways to find out an update is required or, not are as: Explicit update

Modifyand removing a sequence-sequences, Modify a sequence: ALTER SEQU...

Modify a sequence: ALTER SEQUENCE SEQSS INCREMENT 2 MAXVALUE 3000; Removing a sequence: DROP SEQUENCE SEQSS;

Create database for car application, The Database MySQL scripts cars_f...

The Database MySQL scripts cars_for_sale.sql and car_details.sql containing the data to use for this task have been supplied. To complete this task, you need to first create

How many types of data independence have, Types of data independence D...

Types of data independence Data independence can be classified into the following two types: Physical Data Independence: This means that for any change made in the physi

What is the meaning of recovery, What is the meaning of Recovery? In d...

What is the meaning of Recovery? In deferred update methods, if a transaction fails before arriving its commit point, it will not have altered the database in any way, so UNDO

What are the three types of data sources, What are the three types of data ...

What are the three types of data sources used with ODBC? An ODBC file data source is a file that can be shared between database users. An ODBC system data source is one that is

Write short notes on domain relational calculus, Write short notes on domai...

Write short notes on domain relational calculus The domain relational calculus uses domain variables that take on values from an attribute domain rather than values for whole t

Data models, what is stracture of dabms

what is stracture of dabms

Write Your Message!

Name

Email id

Message

Verfication Code

User Account

All Pages