What is a transaction and what are ACID properties?

Question Posted / swapna

14 Answers
73145 Views
Config Systems, IBM, TCS, Virtusa, I also Faced
E-Mail Answers

Answers were Sorted based on User's Feedback

What is a transaction and what are ACID properties?..

Answer / pardeep jangra

A transaction is a unit of program execution that
accesses and possibly updates various data items.
! A transaction must see a consistent database.
! During transaction execution the database may be
inconsistent.
! When the transaction is committed, the database must
be consistent.
ACID PROPERTIES
Atomicity- requires that each transaction is "all or
nothing": if one part of the transaction fails, the entire
transaction fails, and the database state is left unchanged.
An atomic system must guarantee atomicity in each and every
situation, including power failures, errors, and crashes.
Consistency

The consistency- property ensures that any transaction will
bring the database from one valid state to another. Any data
written to the database must be valid according to all
defined rules, including but not limited to constraints,
cascades, triggers, and any combination thereof.
Isolation

Isolation- property ensures that the concurrent execution of
transactions results in a system state that could have been
obtained if transactions are executed serially i.e. one
after the other.[citation needed]
Durability

Durability- means that once a transaction has been
committed, it will remain so, even in the event of power
loss, crashes, or errors. In a relational database, for
instance, once a group of SQL statements execute, the
results need to be stored permanently (even if the database
crashes immediately thereafter).

Is This Answer Correct ?

1 Yes

1 No

What is a transaction and what are ACID properties?..

Answer / ravina

A transaction is a sequence of sql Operations(commands),
work as single atomic unit of work. To be qualify
as "Transaction" , this sequence of operations must satisfy
4 properties , which is knwon as ACID test.

A(Atomicity):-The sequence of operations must be atomic,
either all or no operations are performed.

C(Consistency):- When completed, the sequence of operations
must leave data in consistent mode. All the defined
relations/constraints must me Maintained.

I(Isolation): A Transaction must be isolated from all other
transactions. A transaction sees the data defore the
operations are performed , or after all the operations has
performed, it can't see the data in between.

D(Durability): All oprtaions must be permanently placed on
the system. Even in the event of system failure , all the
operations must be exhibit.

Is This Answer Correct ?

0 Yes

0 No

What is a transaction and what are ACID properties?..

Answer / sonu

A transaction is a sequence of sql Operations,
work as single atomic unit of work. To be qualify
as a "Transaction" , this sequence of operations must satisfy 4 properties , which is knwon as ACID test.any database must follow these acid properties.

Atomicity:-The sequence of operations must be atomic,
either all or no operations are performed.

Consistency:- When completed, the sequence of operations
must leave data in consistent mode. All the defined
relations/constraints must me Maintained.

Isolation: A Transaction must be isolated from all other
transactions. A transaction sees the data before the
operations are performed , or after all the operations has
performed, it can't see the data in between.

Durability: All oprtaions must be permanently placed on
the system. Even in the event of system failure , all the
operations must be exhibit.

Is This Answer Correct ?

7 Yes

10 No

What is a transaction and what are ACID properties?..

Answer / abdul malik(new college)

A-Atomacity
C-Consistency
I-Isolation
D-Durability
Atomacity-eiher all operations of the transaction are
reflected properly in the database are none all.
Consistency-Execution of transaction in isolation (ie)with
no other transaction executing concurrently.preserve
the consistency of the database.
Isolation-even though multiple transaction may execute
concurrently.
Durablity-
after a transaction complete successfully the changes it has
made to the database presist even if there are system
failure.
These are called ACID properties.

Is This Answer Correct ?

17 Yes

22 No

Post New Answer