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# ACID

Describe about What is ACID

ACID is the fundamental concept of database including :

* Atomicity 
* Consistency
* Isolation
* Durability

### Atomicity

Atomicity mean everything is not able to split or separate. It mean all of queries in the transaction need to succeed If not then it will rollback or the database is crashed by itself it still rollback as well before it restart again.

### Isolation

These are the main thing that you need to know first.

1. Can our transaction see  changes made by other transaction ? It mean when you read the data in #1 transaction and at the same time in another transaction #2 update the value then #1 should see the update value or not.
2. Read phenomena -> Reading Situation that is able to happen)
3. Isolation level -> It is the way that we handle to resolve read phenomena problem

#### Read Phenomena 

including 

1. Dirty Reads
2. Non-repeatable read
3. Phantom Read
4. Lost update