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

ERD, #question.ERD of any car

#question.ERD of any car

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)

MANAGEMWNT OF PRINCILES AND TECHNIQUES., HOW TO SOLVE THE LP Problems by si...

HOW TO SOLVE THE LP Problems by simplex method?z=x1+-3x2+2x3

State about the advance object design, ADVANCE OBJECT DESIGN Introduct...

ADVANCE OBJECT DESIGN Introduction Analysis is the initial step of the OMT methodology. It is apprehensive with devising a precise, concise, correct and understandable mo

What is 2nf, What is 2NF? A relation schema R is in 2NF if it is in 1NF...

What is 2NF? A relation schema R is in 2NF if it is in 1NF and every non-prime attribute A in R is fully functionally dependent on primary key.

Optimistic concurrency contents -write-set(t), write-set(T): Each data ite...

write-set(T): Each data items that are written by a transaction T

OLD HOME POLICIES, Write an sql statement to find what is the percentage of...

Write an sql statement to find what is the percentage of home policies which are from the state of Arizona out of all Home policies by Policy Value.

Give concurrent sub states diagram for the classroom, Give Concurrent sub s...

Give Concurrent sub states diagram for the classroom and exam held. In Figure, simultaneous substrates have been taken. After passing Minor 1 test you could give Minor 2 test. T

Determine the three views of data, Determine the Three Views of Data We...

Determine the Three Views of Data We know that the similar thing, if viewed from dissimilar angles produces difference sights. Similarly, the database that we have formed alrea

System level permissions-data control, System level permissions : With the ...

System level permissions : With the use of data dictionary you can view them.       Let us take the table name as user_sys_privs (used in oracle).       DESCRIBE USER_SYS_PRI

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