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.
Describe analysis of access paths To describe analysis of access paths, consider an example of the design of a company's employee skills database. A part of the object model fr
Consider the subsequent relations RENTER(rno, fname, lname, address, tel_no, pref_type, max_rent) VIEWING(rno, pno, date, comment) PROPERTY_FOR_RENT( pno, street, area ,city,
Breaking into Subsystems Decomposition is a significant technique for coping with complexity based on idea of divide and conquers. In dividing a problem into sub problems, the
What is known as clustering file organization? In the clustering file organization, records of several dissimilar relations are stored in the similar file.
1) Define a job scheduling strategy that will meet business requirement of reporting availability by 6am CST for the following cubes? Show the job scheduling dependencies in a pict
Describe the algorithm for updating indices for a single level index when a record is (i) Inserted (ii) deleted What will be the modification if there are multilevel in
An instance of relational schema R (A, B, C) has distinct values of A including NULL values. then A is a candidate key or not? If relational schema R (A, B, C) has distinct val
What is called query processing? Query processing refers to the range of activities included in extracting data from a database.
List the table modification commands in SQL? A) Deletion B) Updates C) Insertion D) Update of a view
Develop Database academic assignment Project Description: For a provided set of instructions in a case study design Entity Relationship Diagram. - Entity Relationship Diag
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