SQL Transaction Characteristics Explained

SQL transactions have the following characteristics:

1. Atomicity: A transaction is a single unit of work that is indivisible; it either all succeeds or all fails. If any part of the transaction fails, the entire transaction will be rolled back to its initial state, meaning all operations will be undone.
2. Consistency: Before and after the execution of a transaction, the database’s integrity constraints and business rules remain consistent. If the transaction is successful, the database’s state will transition from one consistency state to another.
3. Isolation: When multiple transactions are executed simultaneously, each transaction’s operations should be independent of others, without interference. This is achieved by controlling the interaction between transactions through the use of isolation levels (such as read uncommitted, read committed, repeatable read, and serializable).
4. Durability: Once a transaction is committed, the modifications made to the database will be permanently saved, even in the event of system failure. The database should be able to recover to the state it was in after the transaction was committed.