When are two schedules said to be view equivalent, Database Management System

Assignment Help:

When are two schedules said to be view equivalent?    

Ans: Two schedules that is denoted as S and S' are said to be view equivalent if the subsequent three conditions are met

1)  For every data item Q, if a transaction Ti reads the initial value of Q in schedule S, after that transaction Ti should in schedule S'  also read the initial value of Q.

2)  For every data item Q, if a transaction Ti executes read(Q)  in schedule S and that value was generated by Tj (if any) , then transaction Ti must in schedule S'  as well read the value of Q generated by Tj.

3)  For every data item Q, if a transaction if any that carries out the final write(Q) in schedule S should perform the final write(Q) in schedule S'.


Related Discussions:- When are two schedules said to be view equivalent

What is meant by heuristic optimisation, What is meant by heuristic optimis...

What is meant by heuristic optimisation?  Discuss the main heuristics that are applied during query optimisation.  Ans:  In heuristic optimization, heuristics are employed to r

Create a technology web server, Database design Database tables will be...

Database design Database tables will be created for you on the Technology web server. The schema will be as follows. Please note that this is a simplified database structure, d

Difference between sql and sql*plus, Difference between SQL and SQL*Plus ...

Difference between SQL and SQL*Plus SQL SQL*Plus SQL is a language SQL *Plus is an environment It   is   bas

Data control, Identify the need and use of data control through problem sol...

Identify the need and use of data control through problem solving, illustration

Er diagram, Design a generalization–specialization hierarchy for a motor-ve...

Design a generalization–specialization hierarchy for a motor-vehicle sales company. The company sells motorcycles, passenger cars, vans, and buses. Justify your placement of attrib

What are the aggregate objects in the data dictionary, What are the aggrega...

What are the aggregate objects in the data dictionary? Views Match codes Lock objects.

Failure controlling methods, Failure Controlling Methods: Failures can be h...

Failure Controlling Methods: Failures can be handled using different recovery methods that are talk about later in the unit. But the first question is doing we really require recov

Designing a Human Resources Database LASA1, Scenario: You are a freelance ...

Scenario: You are a freelance database designer who has just been contacted by a small software development company named Altair Software. The president of the company has asked

What is object containment, What is object containment? References amon...

What is object containment? References among objects can be used to model dissimilar real-world concepts.

Cataloguing, differences between a classified catalog and a dictionary cata...

differences between a classified catalog and a dictionary catalog

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