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

Difference between operating system and database security, Difference betwe...

Difference between Operating System and Database Security Security within the operating system can be executed at various levels ranging from passwords for access to system, t

Explain the exec statement in sql, Explain the Exec statement in SQL An...

Explain the Exec statement in SQL Ans: Exec statement has the structure    EXEC SQL END-EXEC   Embeded SQl statements are of a form identical to non embedded SQL statem

Database incident table, The Incident table, with an auto-incrementing in...

The Incident table, with an auto-incrementing incident number, etc, looks like: incident_num reporter date time incide

Er diagram, a publishing company produce scientific books on various subjec...

a publishing company produce scientific books on various subjects. the books are written by authors who specialize in one particular subject. the company employs editors who, not n

What is a database, What is a database? At any given time, they're sto...

What is a database? At any given time, they're storing a tremendous amount of information - inventory, in the case of Amazon, messages and interrelationships in the case of Tw

State about the tables- DBMS, State about the Tables- DBMS Data is sto...

State about the Tables- DBMS Data is stored in columns and rows (much like a spreadsheet -main difference is how data is organised). Every row in a table is known as a record

What subschema expresses, What subschema expresses ? A subschema expres...

What subschema expresses ? A subschema expresses the external view. (External schemas are called also called as subschemas)

Produce a set of relations - normalisation, Produce a set of relations (equ...

Produce a set of relations (equivalent to the Finkelstein entity list) in third normal form (3NF) from the following un-normalised relation. You must use the Finkelstein methodolog

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