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	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 result of the union operation between r1 and r2, The result of the UNIO...

The result of the UNION operation between R1 and R2 is a relation that includes? The result of the operation between R1 and R2 includes all the tuples of R1 and R2 which have c

Database Design For Inventory, how design database from begining

how design database from begining

Views-data control, Views A view is like a window by which data from ta...

Views A view is like a window by which data from tables can be changed or viewed. The table on which a view is based is known as Base table. The view is stored as a SELECT stat

Eer diagram, Design an EER schema for the following application and transla...

Design an EER schema for the following application and translate the EER schema into relational schemas (and constraints). It is possible that some requirements cannot be captured

RDBMS, DISADVANTAGES OF RDBMS

DISADVANTAGES OF RDBMS

Define the basic operations of the relational algebra, Define the basic ope...

Define the basic operations of the relational algebra? Ans: Basic operators of relational algebra are: 1. Union (∪) - Selects tuples which are in either P or Q or in bot

What is called query processing, What is called query processing? Query...

What is called query processing? Query processing refers to the range of activities included in extracting data from a database.

Define the term e-government, Question: (a) Define the term e-Governme...

Question: (a) Define the term e-Government and briefly explain, using appropriate examples, the aspects it covers. (b) Give four reasons as to why a country should adopt e

Exclusive lock, Exclusive lock It is asked for by a transaction on...

Exclusive lock It is asked for by a transaction on a data item that it wants to update. No other transaction can put either a shared lock or an exclusive lock on a dat

Define lock, Define lock? Lock is the most common used to execute the r...

Define lock? Lock is the most common used to execute the requirement is to permit a transaction to access a data item only if it is currently holding a lock on that item.

Write Your Message!

Name

Email id

Message

Verfication Code

User Account

All Pages