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

Write the sql code, Express the following queries in SQL: (a) Write the...

Express the following queries in SQL: (a) Write the SQL code that will create ALL the four tables given in the appendix. Your answer should not contain the primary key and

Define atomicity and aggregation, Atomicity : Either all functions are lai...

Atomicity : Either all functions are laid out or none are. Users could not have to think about the effect of incomplete operations. DBMS ensures this by undoing the functions

ERD, entity relationship diagram about finance

entity relationship diagram about finance

Define the concept of generalization, Define the concept of generalization ...

Define the concept of generalization A generalization is relationship between specific kind of thing and general thing. It is also known as "is-a-kind-of" relationship. Inher

Explain difference between volatile, Explain the difference between the thr...

Explain the difference between the three storage types - volatile, non volatile and stable.             Ans: Volatile storage: if storage media loses data while power goes off,

Logical design part 1, create an e-r diagram usuing graphical dipicted soft...

create an e-r diagram usuing graphical dipicted software that could theoritically be used in resturant application

Define database management system, Define database management system? D...

Define database management system? Database management system (DBMS) is a set of interrelated data and a combination of programs to access those data.

Explain function group, What is a function group? A function group is ...

What is a function group? A function group is a collection of logically related modules that share global data with every other.  All the modules in the group are contained in

Explain an attributes, What are attributes? Give examples. An entity is...

What are attributes? Give examples. An entity is shown by a set of attributes. Attributes are descriptive properties possessed by every member of an entity set. Example: pos

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