How are transactions used?

Transactions: A transaction is a sequence of operations performed as a single logical unit of work ( OR ) A Transaction is a Logical unit of work. Properties of Transactions: Every logical unit of work must exhibit four properties to consider that as a transaction. Those properties are called as ACID Properties. Atomicity: Consider a transaction having n number of queries either all these n no.of queries has to be successfully completed or all n no.of queries should fail. This property is called as Atomicity. Consistency: After completion of a transaction all the data should be left in a consistent state. That means when you insert a new record in a table called Students and for example if the table is having any associated indexes , after inserting the data into the table the associated indexes should be updated appropriately. Isolation: as per isolation no two concurrent transaction should be allowed to act upon a single data. Durability: After completion of a transaction the data modified by the transaction should be stored permanently in the DB even in case of system failure. sql interview questions