Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
Two Phase Locking (2PL)
The two-phase locking protocol having of two phases:
Phase 1: The lock acquisition phase: If a transaction T needs to read an object, it wants to obtain the S (shared) lock. If T needs to modify an object, it wants to obtain X (exclusive) lock. No conflicting locks are granted to a transaction. New locks on items can be obtained but no lock can be released till all the locks needed by the transaction are obtained.
Phase 2: Lock Release Phase: The existing locks can be released in any order but no new lock can be obtained after a lock has been released. The locks are held only till they are needed.
Normally the locks are taken by the DBMS. Any legal schedule of transactions that follows 2 phase locking protocol is sured to be serialisable. The 2 phase locking protocol has been confirmed for it correctness. Though, the proof of this protocol is beyond the scope of this Unit. You can refer to more readings for more details on this protocol.
need requirement analysis for database management of stock market
Example -GRANT CREATE SESSION TO MCA12; (This command gives system level permission on creating a session - not portable) GRANT SELECT ON EMP TO MCA12; (Object level permi
What do you understand by RAID? Explain RAID Level 4 and Level5? RAID - It is stands for Redundant Array of Inexpensive Disks (as named by the inventor), or alternatively Re
why three level architecture had been developed/
System R was developed and designed over a period of 1974-79 at IBM San Jose Research Company. Its purpose was to illustrate that it is possible to create a Relational System tha
Project Description: I want to build a card playing Website. The user should be able to 1. Login. 2. Have profile access. 3. Put money into the site. 4. Selects t
Problem 1. Write an assembly program to find the smallest among two numbers Writing an assembly program to find the smallest among two numbers 2. Explain the intern
I need help in doing my dbms project
How many types of users works on database? Users are differentiated through the way they expect to interact along with the system (i) Application programmers-interact with
Question 1: a) What is the difference between a non-impact and impact printer? b) Which type of printer is generally used in a supermarket to print your receipt? Describe
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!
whatsapp: +91-977-207-8620
Phone: +91-977-207-8620
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd