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 are the four main characteristics of the database, What are the four m...

What are the four main characteristics of the database approach? The four major characteristics of the database approach are: 1. Self-describing nature of a database system. 2.

Managing databases, 10A.53 Code an Oracle Database trigger to enforce the...

10A.53 Code an Oracle Database trigger to enforce the constraint that an employee can never change his or her department. 10A.54 Code an Oracle Database trigger to allow the

How to rearrange the execution order for efficiency, Rearrange the Executio...

Rearrange the Execution Order for Efficiency  Rearranging execution order for efficiency means executing such job that requires less execution time. By rearranging the object

Sql insert statements, Submit SQL INSERT Statements that will populate the ...

Submit SQL INSERT Statements that will populate the database with sample data.  You must insert at least 5 records into each table in your database.Submit your SQL INSERT Statement

Entity relationship diagram, Ask questApollo Hospitals (AH) is a popular me...

Ask questApollo Hospitals (AH) is a popular medical service provider in Oman. AH wants to automate its business functions into an information system. The proposed information syst

Develop a web site to present decision tree structure, I am going to develo...

I am going to develop a web site to present decision tree structure. For this, I want a web application with AJAX technology to connect the database and prepare the decision tree's

Determine the two special events, What are two special events? The two ...

What are two special events? The two special events are as "entry" and "exit". Any action which is marked as linked to entry event is executed whenever given state is entered v

Which product produces the relation that has attributes, Which product prod...

Which product produces the relation that has attributes of R1 and R2 ? Cartesian product produce the relation which has attributes of R1 and R2

A weak entity set and its identifying relationship, Q.  Define a weak entit...

Q.  Define a weak entity set and its identifying relationship. List the necessary conditions for a meaningful identifying relationship set of a weak entity set.    Entity is a t

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