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

The average amount of their orders , Make SQL statements for the following ...

Make SQL statements for the following scenarios. Your response should contain SQL statement, output and any other assumptions you have made to arrive at the answer. For Colorado cu

Design and implement a database system, Safe Banking is a Canberra based cr...

Safe Banking is a Canberra based credit union, which has several branches around Canberra and Queanbeyan. YOU have taken over Safe Banking. YOU need to create a database that organ

Explain hierarchical model, Explain Hierarchical Model ? Hierarchical ...

Explain Hierarchical Model ? Hierarchical Model - It was established to model several kinds of hierarchical organizations which exist in the real world. It uses tree structur

What is the disadvantage of a call by reference, What is the disadvantage o...

What is the disadvantage of a call by reference? During a call by reference damage or loss of data is not restricted to the subroutine, but will instantly lead to alters to th

Can you scan double-sided documents and remove blank pages, Can you scan do...

Can you scan double-sided documents - and remove blank pages? Our software and imaging systems supports duplex scanning, at the same time scanning both sides of a page. Program

Hierarchical data representation model, Examples:- Hierarchical Model: I...

Examples:- Hierarchical Model: It tells data as and relationships by hierarchy of data values. Figure illustrates an example of hierarchical model. Now a day's these models are

Which types of data supported by mysql, Which types of data supported by My...

Which types of data supported by MySQL for Time and Date formats?  MySQL supports a number of time and date column formats: Some of them are 1) DATE 2) DATETIME 3) TIM

Pl/SQL, I need solution of the question posted at http://www.expertsmind.c...

I need solution of the question posted at http://www.expertsmind.com/questions/sql-query-for-testing-triggers-and-stored-procedures-30140149.aspx

Determine Which is not a consequence of concurrent operation, Determine Whi...

Determine Which is not a consequence of concurrent operations? Ans: Update anomaly.

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