Transaction Isolation Level

Syntax :

SET TRANSACTION ISOLATION LEVEL
{ READ COMMITTED
READ UNCOMMITTED
REPEATABLE READ
SERIALIZABLE
}

1. Read Uncommitted: current transaction can read rows modified by other not yet committed transactions
2. Read Committed: current transaction cannot read rows modified by other not yet committed transactions
3. Repeatable Read: read committed + no other transaction can modify data that has been read by the current transaction, they can just insert
4. Snapshot: current transaction can only recognize committed data modification before the start of the current transaction.
5. Serializable: repeatable read except other transactions cannot insert rows with key values that fall in the range of keys read in the current transaction.