Transaction

What is a Transaction?

A transaction can be defined as a group of tasks.

A simple task is the minimum processing unit that cannot be divided further.

Example: Transfer $500 from X account to Y account.

Open_Account(X) 
Old_Balance = X.balance 
New_Balance = Old_Balance - 500 
X.balance = New_Balance 
Close_Account(X)

Open_Account(Y) 
Old_Balance = B.balance 
New_Balance = Old_Balance + 500 
Y.balance = New_Balance 
Close_Account(Y)

States of Transaction

Src: https://www.tutorialspoint.com/dbms/dbms_transaction.htm

src:guru99.com

• Active: When the transaction's instructions are running, the transaction is active.

• Partially Committed: After completing all the read and write operations, the changes are made in the main memory or local buffer.

• Committed: It is the state in which the changes are made permanent on the DataBase.

• Failed: When any instruction of the transaction fails.

• Aborted: The changes are only made to the local buffer or main memory; hence, these changes are deleted.