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Technical Discussion :: DBMS

81. What is a transaction and ACID properties in DBMS?

Answer:

A transaction is a very small unit of a program and it may contain several lowlevel tasks. A transaction in a database system must maintain Atomicity, Consistency, Isolation, and Durability − commonly known as ACID properties − in order to ensure accuracy, completeness, and data integrity.




  • Atomicity − This property states that a transaction must be treated as an atomic unit, that is, either all of its operations are executed or none. There must be no state in a database where a transaction is left partially completed. States should be defined either before the execution of the transaction or after the execution/abortion/failure of the transaction.

  • Consistency − The database must remain in a consistent state after any transaction. No transaction should have any adverse effect on the data residing in the database. If the database was in a consistent state before the execution of a transaction, it must remain consistent after the execution of the transaction as well.

  • Durability − The database should be durable enough to hold all its latest updates even if the system fails or restarts. If a transaction updates a chunk of data in a database and commits, then the database will hold the modified data. If a transaction commits but the system fails before the data could be written on to the disk, then that data will be updated once the system springs back into action.

  • Isolation − In a database system where more than one transaction are being executed simultaneously and in parallel, the property of isolation states that all the transactions will be carried out and executed as if it is the only transaction in the system. No transaction will affect the existence of any other transaction.

Asked In :: Wipro Syntel Inc. Sapient Sopra Steria

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Chaitenya Malviya2 months ago

Dear Raj,

               I am good here, hope you are also doing well. Last month the heritage walk conducted in our city, where i came to know about many incredible buildings and sites, which are not commonly known to all of us.

There i got a chance to meet U.N. secretory general, that was a great experience for me, and knowing of your our city is a great pleasure.

loving you,


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vignesh vishwa2 months ago
hi everyone,
Ya..television has impact on children,but in same television help the children to learn good thing and humanity.
Sometimes we have to think out of the box,nowadays there are many programmes which help the children in gaining academic and creative knowledge too, instead of getting used to of watching television we have limit the children a certain time for watching television...by doing this they wont be distracted from thier studies and also they will be updated and satisfied.
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R.MohanRaj B.E3 months ago

Dear client,



I am writing this mail to inform you  that  we are celebrating the occasion of Durka
festival from   8th October to 10
October. due to the fact of our cultural festival, Despite that will not able
to send the report during this period.



I apologize for that inconvenience unable to send a report
on time. we assure you that we will send the report on 11th October.



 



I looking forward  to
hearing your response

|| Reply
Deepak Pandey3 months ago

Dear Mr. Gill Roy,

we apologize for the delay in your service. Your payment process which was scheduled for 10th May (Friday) is delayed by 7 days due to 3 days of an unexpected power outage and recovery process. We are trying to process it as fast as possible. we are ensuring you that it will not recur any more. Kindly stay tuned with us.

Thank you,

Regards

Abhimanyu 

Project manager



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Deepak Pandey3 months ago

Respected sir,

I am glad to inform you that our institute is going to organize the yearly happening fest 'TECHNICAL SYMPOSIUM' again this year. A lot of new students are going to participate in this fest. It's going to be a large gathering of new technical lovers. We are inviting your students to attend the fest and participate in it to provides new innovative ideas.

thank you 

yours sincerely 

SUNDER 

collage srepresentative 


|| Reply