It is said to be set of read or write operations
A Transaction is said to be a query if it contains either a read or update operation
Commit is a point of no return, once a transaction is commited we are certain that, the changes to the database are permanent
ACID Properties of a General Purpose Databases
An action is said to be atomic, if it either completely done or not at all.
A transaction transforms the database from one consistent state to another consistent state. A state is said to be a set of transactions.
Until and unless a transaction is committed, the actions of it are not visible to any other transactions
After commit, the changes made to the databases are permanent
Conventional Databases will follow the ACID properties and it never violates