SQL - TRANSACTIONS
A transaction is a unit of work that is performed against a database. Transactions are units or sequences of work accomplished in a logical order, whether in a manual fashion by a user or automatically by some sort of a database program.
Properties of Transactions
Transactions have the following four standard properties, usually referred to by the acronym ACID −
Atomicity − Ensures that all operations within the work unit are completed successfully; otherwise, the transaction is aborted at the point of failure and previous operations are rolled back to their former state.
Consistency − Ensures that the database properly changes states upon a successfully committed transaction.
Isolation − Enables transactions to operate independently of and transparent to each other.
Durability − Ensures that the result or effect of a committed transaction persists in case of a system failure.