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

Abap/4 program, It is not possible to make an ABAP/4 program, which having ...

It is not possible to make an ABAP/4 program, which having only Subroutines. False. We can make ABAP/4 program, which having only Subroutines.

Balance transfer, Scenario 1: Power goes out after the first instruction. ...

Scenario 1: Power goes out after the first instruction. What happens?

Need web-based database, Our company hires independent contractors to insta...

Our company hires independent contractors to install equipment at precise locations across North America. We want to track the installation data and generate reports. The compan

Write short note on data models, Write short note on Data models? Data...

Write short note on Data models? Data models: A data model is an abstract model which elaborates how data is represented and accessed. The term data model has two commonly ac

Design a large scale system, Question: (a) Why is it important to know...

Question: (a) Why is it important to know the architecture rather than to start requirement capture when designing a large scale system? (b) Who are the different people in

What are the properties of transaction, What are the properties of transact...

What are the properties of transaction? There are three properties of transactions :- A)     Atomicity B)      Consistency C)       Isolation

Sorting field groups we cannot use more than one key field, While sorting f...

While sorting field groups we cannot use more than one key field False.

Explain the role of a database administrator, Explain the Role of a databas...

Explain the Role of a database administrator a. Defining the Schema   The DBA describes the schema which consists of the structure of the data in the application. The DBA

Explain er relationship model, Explain ER Relationship model? An entity...

Explain ER Relationship model? An entity-relationship model (ERM): An entity-relationship model (ERM) is an abstract theoretical illustration of structured data. Entity-relatio

Process-oriented decompositions, Process-oriented decompositions Pr...

Process-oriented decompositions Process-oriented decompositions divide complex process, task or function into simpler sub processes until they get simple enough to be deal

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