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

Develop a fragment of a hypothetical system, The objectives of this assignm...

The objectives of this assignment are:  - to develop skills in the design of database driven applications  - to develop skills in applying SQL to implement the relational and

What are views explain how views are different from tables, What are views?...

What are views? Explain how views are different from tables? A view in SQL terminology is a one table in which is derived from other tables. These other tables could be base t

What is the initial step for object-oriented designing, What is the initial...

What is the initial step for object-oriented designing The initial step for object-oriented designing is object modeling. Before we go into deep about object modeling first of

Write short notes on tuple relational calculus, Write short notes on tuple ...

Write short notes on tuple relational calculus. The tuple relational calculation is anon procedural query language. It defines the desired information without giving a particul

Describe the basic steps involved in recovery, Question: One of the tas...

Question: One of the tasks a database management system must perform is to ensure that the data is still intact in the face of software and hardware failure. This task is known

Define raid structure, Define raid? Briefly explain it? A range of disk...

Define raid? Briefly explain it? A range of disk organization methods, collectively called redundant arrays of independent disks (RAID) o   Improvement of reliability throug

ER diagrams, explain exhaustively the problems associated with ER diagrams....

explain exhaustively the problems associated with ER diagrams. include illustrations in your answer

In which relational modes cardinality is termed, In which relational modes,...

In which relational modes, cardinality is termed? Answer : Cardinality is termed in a number of tuples relational modes.

Create a new user-data control, Create a new user : CREATE USER IDENTI...

Create a new user : CREATE USER IDENTIFIED BY Example: //CREATE USER MCA12 IDENTIFIED BY W123 Grant: It is used to give database access permission to users. It is of

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