Durability-transaction , Database Management System

Assignment Help:

Durability: This property necessitates that once a transaction has committed, the changes made by it be never lost because of subsequent failure. Thus, a transaction is also a basic unit of recovery.

A transaction has many states of implementation. These states are displayed in Figure.

                                        2117_Durability-transaction.png

                                                             Figure: States of transaction execution

A transaction is started as a program. From the initial state as the transaction is scheduled by the CPU it moves to the Implement state, though, in case of any system error at that point it may also be gone into the Abort state. During the implement transaction changes the data values and database gone to an inconsistent state. On successful completion of transaction it gone to the Commit state where the durability feature of transaction makes sure that the changes will not be lost. In case of any error the transaction moves to Rollback state where all the changes made by the transaction are not done. Therefore, after rollback or commit database is back into consistent state. In case a transaction has been rolled back, it is started as a latest transaction. All these states of the transaction are shown in above Figure.


Related Discussions:- Durability-transaction

E-r diagram, Let us now make the E-R diagram for the student database as pe...

Let us now make the E-R diagram for the student database as per the explanation given in the previous section. We can also states the overall logical structure of a database usi

Define the term- making common behaviour abstract, Making Common Behaviour ...

Making Common Behaviour Abstract Let us define abstraction "Abstraction means to focus on the necessary, inherent aspects of an entity and ignoring its accidental features". O

What is an index, What is an index? An index is a structure that helps ...

What is an index? An index is a structure that helps to place desired records of a relation quickly, without probing all records.

Whta is the advantage of the database management approach, Whta is the adva...

Whta is the advantage of the database management approach? The advantage of the database management approach is data is integrated and can be accessed by multiple programs.

Determine the concept of process, Determine the concept of Process Pro...

Determine the concept of Process Process: A process transforms the data values. It is represented as ellipse containing a description of transformation. Each procedure has a

Using sql create a view rs for the relations r and s, Using SQL create a vi...

Using SQL create a view RS for the relations R and S. The view consists of the columns A and D renamed as X and Y in that order. Insert a tuple into it. Show the contents of t

What is e-r model, What is E-R model? This data model is based on real ...

What is E-R model? This data model is based on real world that having of basic objects called entities and of relationship between these objects. Entities are explained in a da

Draw the precedence graph, Draw the precedence graph of the following sched...

Draw the precedence graph of the following schedule and determine whether the schedule is serializable. (Note that all instructions, except lock and unlock, are omitted. We assume

What are the problems in database normalization, What are the problems if o...

What are the problems if one were not to normalize?  When do these problems surface?           Ans:  Database normalization, sometimes considered to as  canonical synthesis, is

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