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

Discuss the count function, Discuss the count function? The COUNT funct...

Discuss the count function? The COUNT function used returns the number of tuples or values fixed in a query. The count function comprises two types of syntax: (1) COUNT (*)

Mappings between levels and data independence, Mappings between Levels and ...

Mappings between Levels and Data Independence The 3 levels of abstraction in the database do not exist separately of each other. There must be some correspondence, or mapping

Command line interfaces, Command Line Interfaces: These are interactive int...

Command Line Interfaces: These are interactive interfaces, character-based that let you use the complete power and functionality of the DBMS query language directly. They permit yo

Explain interfaces for parametric users, Explain Interfaces for parametric ...

Explain Interfaces for parametric Users? Interfaces for Parametric Users - Parametric users, such as bank tellers, frequent have a little set of operations in which they must p

Create a database of a motor bike racing club, You have a friend that runs ...

You have a friend that runs a motor bike club that holds racing events at various venues on weekends, on a monthly basis. Some venues are private race tracks and some are dirt trac

Create records in a table - data structures, In this exercise you will crea...

In this exercise you will create ten records, each containing the following fields: student name, class:  Freshman, Sophomore, Junior or Senior, Major:  Liberal Arts or General Sci

What is object oriented model, What is Object Oriented model? This mod...

What is Object Oriented model? This model is based on collection of objects. An object has values stored in instance variables with in the object. An object also having bodies

Need point of sale software for pizza restaurant, Project Description: N...

Project Description: Need Point of Sale software for pizza restaurant. Delivery and take out service, client's database, inventory control, order history, last order, order from

Obtain the house numbers street wise from database, For the relations answe...

For the relations answer the following queries in SQL Street (name, location, city) House (number, street_name) Lives (name, house_number) (i) Obtain the names of persons who liv

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