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 difference between primary index and secondary index, What is diffe...

What is difference between primary index and secondary index? Primary Index a) It is an ordered file whose records are of fixed length along with two fields. b) Only base

Structure of client server systems, Structure of Client Server Systems: In ...

Structure of Client Server Systems: In client/server architecture, clients show users who require services while servers give services. Both client and server are a combination of

Differentiate between a unique key and a primary key, Differentiate between...

Differentiate between a unique key and a primary key. - By default, clustered index on column are created by primary key while nonclustered index are created by unique key.

Write short notes on domain relational calculus, Write short notes on domai...

Write short notes on domain relational calculus   The domain relational calculus uses domain variables that take on values from an attribute domain rather than values for whole

Student database, tell me the functionality,advantages and disadvantages of...

tell me the functionality,advantages and disadvantages of student database

Pl/SQL, I need solution of the question posted at http://www.expertsmind.c...

I need solution of the question posted at http://www.expertsmind.com/questions/sql-query-for-testing-triggers-and-stored-procedures-30140149.aspx

Define two phase commit, Define Two phase commit Two phase commit: To m...

Define Two phase commit Two phase commit: To make sure atomicity, all the sites where a transaction is being executed must agree on the final outcome of the execution. The tran

DBMS, what is specialization?

what is specialization?

Er diatgrams, Ask q“A database will be made to store information about pati...

Ask q“A database will be made to store information about patients in a hospital. On arrival, each patient’s personal details (name, address, and telephone number) are recorded wher

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