Unrepeatable reads-problems of concurrent transactions, Database Management System

Assignment Help:

Unrepeatable reads: Assume T7 reads X twice during its implementation. If it did not update X itself it could be very disturbing to see a dissimilar value of X in its next read. But this could occur if, among the two read operations, another transaction modifies X.

 

T7

T8

Assumed value of

X=2000

T7

T8

READ X

 

2000

 

 

UPDATE X

 

3000

READ X

 

3000

 

 

Therefore, the inconsistent values are read and results of the transaction may be in fault.

 


Related Discussions:- Unrepeatable reads-problems of concurrent transactions

Recovery techniques, Recovery Techniques: After Reading the types of failur...

Recovery Techniques: After Reading the types of failures and database errors, let us talk about how to recover from the failures. Recovery can be complete using/restoring the previ

State the process of inheritance adjustment, Inheritance Adjustment As...

Inheritance Adjustment As in object oriented analysis and design terms inheritance defines a relationship between classes, where as one class shares structure or behaviour def

Draw the architecture of mysql, Data Base Management System 1. Draw the...

Data Base Management System 1. Draw the Architecture of MySQL and explain about its subsystems briefly. 2. Elaborate with the help of an example the concept of Primary key a

Increased overheads on update-data replication, Increased overheads on upda...

Increased overheads on update : On the drawbacks side, it will need the system to ensure that all replicas of a relation are consistent. This shows that all the replicas of the rel

NORRMALIZATION, Home based assignment Consider an ORDER table with the foll...

Home based assignment Consider an ORDER table with the following attributes: • Order Number (ONo),Customer Number (CNo),Customer Name (CNa),Item Number (INo),Unit Price (UP), Quant

Is siteground database over limit, I am using Siteground. And my databas...

I am using Siteground. And my database is full of limit so need someone who reduces the data which no need. This is very simple and simple task. Skills required are Databa

Text mining, Text Processing: Use readLines to read SOU.txt into R. Cr...

Text Processing: Use readLines to read SOU.txt into R. Create a vector called Pres containing the names of the presidents giving each speech. To do this, rst identify the lin

Max. no. of structures in a table or structure, What is the max. no. Of str...

What is the max. no. Of structures that can be included in a table or structure. Nine.

What is a state chart diagram, What is a state chart diagram? State dia...

What is a state chart diagram? State diagrams (State Chart Diagram) explain all possible states that a particular object can get into, and how object's state changes as result

Create a website for online sales of movies, Niles Video Inc. wants to crea...

Niles Video Inc. wants to create a website for online sales of movies (DVD and videotapes). People will be allowed to register as customers on the website and to update their store

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