Explain the concept of two-phase locking, Database Management System

Assignment Help:

Explain the Concept of Two-phase Locking

It concerns the positions of locking and unlocking operations in each transaction.  In this protocol every transaction issue lock and unlock requests in two phases. 

Growing Phase:  In this phase a transaction might acquire locks but may not release any lock. Here the of locks rises from zero to the maximum for the transaction. 

Shrinking Phase:  In this phase a transaction might release locks but may not obtain any new locks. Here the number of locks reduces from maximum to zero. 

The major concept of this protocol is that, all the locks are first obtained before any of the locks released. No new locks can be granted later than the releasing of any lock.


Related Discussions:- Explain the concept of two-phase locking

Give the general form of sql query, Give the general form of SQL query? ...

Give the general form of SQL query? Select  A1, A2............., An From  R1, R2..............., Rm Where  P

Define the terms physical schema and logical schema., Define the terms 1) p...

Define the terms 1) physical schema 2) logical schema. Physical schema: The physical schema explains the database design at the physical level, which is the lowest level of abs

List and also explain the dissimilar stages of ddlc, List and also explain ...

List and also explain the dissimilar stages of DDLC ?

Database backup, Discuss the importance and characteristics of database bac...

Discuss the importance and characteristics of database backup and recovery procedures, then describe the actions that must be detailed in backup and recovery plan

Explain the need of parallel database, Probelm: a) In the context of OO...

Probelm: a) In the context of OODBMS, define the following terms with appropriate examples. (i) Object class. (ii) Abstract class. (iii) Aggregation. (iv)

Define rule that value of foreign key appear in other table, Determine the ...

Determine the rule that a value of a foreign key should appear as a value of some particular table is called a  Ans: Referential constraint.    The rule that a value of a fo

What is database utility, What is database utility? Database utility is...

What is database utility? Database utility is the interface among the ABAP/4 Dictionary and the underlying the SAP system.

Skills required, wrie a report on whether a BSc n information systems devel...

wrie a report on whether a BSc n information systems develops the skills required by employers in Database administration

Objectives-the structured query language, Objectives After reading this...

Objectives After reading this part, you should be able to: Modify, create, and delete database schema objects; Update database using SQL command; Retrieve data f

Create student db and retrieve all student name in cs, Create a Student dat...

Create a Student database and Retrieve the names of all students majoring in ‘CS' Consider the following relational database: STUDENT (name, student#, class, major) COURSE (co

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