Atomicity – this basically means the transaction works or doesn’t and is sometimes called the “all or nothing” rule. I always liken it to an Atomic bomb because they either work or fail. A failed transaction would then enter a state of rollback.
Consistency – this means only valid data is written to the database. This means if the constraints, keys….. are violated the data would not be committed.
Isolation – this means that multiple transactions should not impact other transactions which are occurring simultaneously.
Durability – this means when a transaction is successful all the pending changes are applied to the database.
SQL stands for Structured Query Language. It is an ANSI standard language which means it is an industry recognised standard language which can be used across a plethora of database management systems. I must caveat the fact that although it is an ANSI standard language minor variations do happen in T-SQL ( SQL Server ), PL/SQL ( Oracle)…..
SQL is used as a programming language in relational database management systems.