Dirty reads-problems of concurrent transactions, Database Management System

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

Describe how you can simplify operations, Describe how you can simplify Ope...

Describe how you can simplify Operations. To simplify operation, one should use inheritance, where possible to use, to reduce the quantity of distinct operations. Introduce new

Data files indices and data dictionary, The indices are accumulated in the ...

The indices are accumulated in the index files. The data is accumulated in the data files. Indices give fast access to data items. For example, a book database may be managed in th

The users who use easy-to-use menu are called, The users who use easy-to-us...

The users who use easy-to-use menu are called ? The users who use easy to use menu are called as Naïve users.

What is business intelligence, Question A What is operational intelligence...

Question A What is operational intelligence? Question B What is Business Intelligence? Explain the components of BI architecture Question C Differentiate between databas

What are the basic merits of decomposition, The basic merits of decompositi...

The basic merits of decomposition. The Advantages of Decomposition 1. Separate person can work on each subsystem. 2. A particular software engineer can specialize in a

Entities, Entities Let us first be aware of the question: What are e...

Entities Let us first be aware of the question: What are entities? An entity is an object of concern used to show the things in the actual world, e.g., table, car, bo

Production management, create an er diagram for production management in fi...

create an er diagram for production management in film industry

State the functional approach of object oriented methods, State the functio...

State the functional approach of object oriented methods Moving from a functional approach to an object oriented one needs a translation of functional model elements into objec

Define the one-way associations, One-way Associations When an associat...

One-way Associations When an association is traversed only in the one direction, then it is implemented as a pointer i.e.an attribute which contains an object reference. If mu

Explain the exec statement in sql, Explain the EXEC statement in SQL A...

Explain the EXEC statement in SQL Ans: All statements which start with EXEC SQL are embedded SQL database statements. High level languages such as C can be employed to write a

Write Your Message!

Name

Email id

Message

Verfication Code

User Account

All Pages