Unrepeatable reads-problems of concurrent transactions, Database Management System

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.

 

Posted Date: 3/12/2013 1:50:06 AM | Location : United States







Related Discussions:- Unrepeatable reads-problems of concurrent transactions, Assignment Help, Ask Question on Unrepeatable reads-problems of concurrent transactions, Get Answer, Expert's Help, Unrepeatable reads-problems of concurrent transactions Discussions

Write discussion on Unrepeatable reads-problems of concurrent transactions
Your posts are moderated
Related Questions
1) Define a job scheduling strategy that will meet business requirement of reporting availability by 6am CST for the following cubes? Show the job scheduling dependencies in a pict

Describe Query evaluation engine? Query Evaluation engine: Vehicle executes low-level instructions obtained through the DML compiler. The Storage Manager Components gives in

Consider the following relations: BRANCH( bno, street, area, city, pcode, Tel_no, Fax_no) STAFF( Sno, Fname, Lname, address, position , salary, bno) Express the subsequent qu

Task Part A. Create an ERD from a business problem. (50 marks) Read the following problem and complete the tasks listed below. THE ABS Blood Bank Australian Blood Services (ABS) i

Eliminate Repeating Groups The problem is, "Find out the list of employees, who knows DB2". For this problem we require to perform an awkward scan of the list looking for re

a project based on normalization with first, second and third normalization. There need to be a diagram also

Explain how you can define an object model of a system. A list of terms that shall be used by end users to describe state and behaviour of objects in system.   Different use

Lack of Redundancy We have talked about the problems of repetition of information in a database. Such repetition should be stay away as much as possible. Let us state once again t

can you create a database for me in oracle/sql

Explain the ANSI SPARC architecture The three-schema architecture is as well known as ANSI SPARC architecture. The aim of the three-schema architecture is to separate the user