When a transaction processing system creates a transaction, it will ensure that the transaction will have certain characteristics. The developers of the components that comprise the transaction are assured that these characteristics are in place. They do not need to manage these characteristics themselves. These characteristics are known as the ACID properties.
If you are creating a database that only has one user who issues SQL statements one at a time,your database implementation would be quite simple. However, most DBMS's are the backend record storage for front-end applications that have multiple users modifying records at the same time. This presents several problems that ACID attempts to define and solve.
ACID stands for Atomicity pronounced "Atom-miss-city", Consistency, Isolation and Durability. Let's look at each one-by-one.
Atomicity:
Either all operations of the transaction are reflected in to the database or none.
Atomicity is pronounced "atom-miss-city". By "atomic" we mean "as a single atom or unit". This is a method of grouping data together as single unit so that the atomic unit of data is either entered into the database or not. It's either "All or nothing" as partially updating a record in the database can have bad results in real-life.
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