Transaction is unit of
work performed in database management system against a database.
Example
1. Transferring money
from Account A to Account B
2. Booking a Movie
ticket
A database transaction
satisfies properties like Atomicity, consistency, Isolation, Durability,
a. Atomicity
A Transaction performed
on a database must complete fully or have no effect. Suppose transferring money
from account 'A' to account 'B' must performed completely. It shouldn't be in
middle state like money deducted from Account 'A' and not credited to account
'B'.
b. Consistency
The guarantee that
operations in transactions are performed accurately, correctly, and with
validity, with respect to application semantic.
c. Isolation
Even though
transactions can execute concurrently, it appears to each transaction that
others executed either before or after it.
d. Durability
Transactions that have
committed will survive permanently on any circumstances like system crash also.
Python DB API provides
two methods commit, rollback for transaction support.
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