ACID Properties
Atomicity
The atomicity property identifies that the transaction is atomic. An atomic transaction
is either fully completed, or is not begun at all. Any updates that a
transaction might affect on a system are completed in their entirety. If
for any reason an error occurs and the transaction is unable to
complete all of its steps, the then system is returned to the state it
was in before the transaction was started. An example of an atomic
transaction is an account transfer transaction. The money is removed
from account A then placed into account B. If the system fails after
removing the money from account A, then the transaction processing
system will put the money back into account A, thus returning the system
to its original state. This is known as a rollback
Consistency
Data is either committed or roll back, not “in-between” case where something has been
updated and something hasn’t and it will never leave your database
till transaction finished. If the transaction completes successfully, then all
changes to the system will have been properly made, and the system will be in a
valid state. If any error occurs in a transaction, then any changes already
made will be automatically rolled back. This will return the system to its
state before the transaction was started. Since the system was in a consistent
state when the transaction was started, it will once again be in a consistent
state.
Isolation
No transaction sees the intermediate results of
the current transaction. We
have two transactions both are performing the same function and running at the
same time, the isolation will ensure that each transaction separate from other until
both are finished.
Durability
Once transaction completed whatever the changes
made to the system will be permanent even if the system crashes right after
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