Dirty reads-problems of concurrent transactions, Database Management System

Dirty Reads: T10 reads a value which is updated by T9. This update has not been committed and T9 aborts.

T9

T10

Value of x old value =

200

T9

T10

UPDATE X

 

500

 

 

READ X

 

500

ROLLBACK

 

200

?

Here T10 reads a value that is updated by transaction T9 that has been aborted. Therefore T10 has read a value that would never exist in the database and hence the trouble. Here the difficulty is primarily of isolation of transaction.

 

Posted Date: 3/12/2013 1:51:39 AM | Location : United States







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

Write discussion on Dirty reads-problems of concurrent transactions
Your posts are moderated
Related Questions
The aims of the project are: 1. To enable the students to undertake the detailed design of a specific plant or process 2. The design projects includes: process selection; und

Using Column aliases Example: To print column names as NAME and ANNUAL SALARY SELECT ENAME "NAME", SAL*12 "ANNUAL SALARY" FROM EMP;

Problem: (a) Given the following relation: Stats(Name,Sex,Children, Occupation, Salary, Tax, Audits) Write SQL code to define the following security constraints: (i) User

Explain Relational model and their use in DBMS? Relational Model - The relational model was first introduced through E.F. Codd of the IBM Research in the year of 1970. The mode

What are the different approaches for database design? There are two basic approaches for database design which are as follows: Attribute driven: It compiles a list of att

What is a super key? A super key is a set of one or more attributes that collectively permits us to recognize uniquely an entity in the entity set.

crete a data base relationship model Entity: Students; Professors; Dormitories buildings; Attributes of students: Name; Address; Dorm;

What are the several forms of identity? a) Value b) Name c) Built-in

Chapter 1 - Profile for the Organization You have to select an organization of your choice and assume that you work for that organization. Now you must prepare a brief profile of t

Table_Name( attribute_1, attribute_2, attribute_3, ….. ,attribute_x) Primary Key ( attribute_1, attribute_2) Foreign Key attribute_4 References Table_Name_2 (repeat for each fore