ACID

The article about certain chemical substances is at Acid

ACID is a concept used with Databases. It is an abbreviation. It stands for

Atomicity - something is either done, or not not. The state of doing it is not visible outside the database.
Consistency - The database is in a legal state at all times. When a transaction occurs, it can not break the rules. These rules are about integrity, that is what is allowed and what is not in a certain location in the database.
Isolation - There can be more than one transaction occurring at the same time. If there is, a certain transaction will not see changes made by other transactions.
Durability - When a transaction is done, it will be committed. After it is committed, it can no longer be undone.

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