In college, I always struggled with ACID properties in DBMS. I knew the full form. Atomicity, Consistency, Isolation, Durability. But honestly, none of it made sense to me back then.
I only understood it properly years later, while working on real systems at Cisco. Let me explain it the way I finally understood it.
Imagine you have a savings account with 25,000 in it. Your bank needs you to maintain a minimum balance of 5,000. And you are transferring some amount to a friend.
A transfer has two steps. Money goes out of your account. Money goes into your friend’s account.
If the first happens and the second fails, you end up losing money and your friend still doesn’t receive anything. That is an inconsistent and unfair state for the system.
Atomicity simply means both steps must succeed together or none of them should happen.
Consistency means your transfer should not break the rules of the system. If you try to send your full 25,000 your balance becomes zero which violates the minimum 5,000 requirement. So the system should not allow it.
Isolation is about timing. Your account gets debited at one moment. Your friend gets credited a little later. If someone checks the balances in between, they should not see half-done data. They should either see the situation before the transfer or after the transfer, but never the messy middle.
Durability is the simple idea that once the money has been transferred and committed, it should never be lost even if there is a crash or power failure.
That’s ACID. The real version. The version that finally clicked for me.
If you want me to simplify more concepts like this, tell me which one I should take up next.
P.S. My new Data Engineering batch starts this Saturday. DM to know more!
Sumit Mittal
In college, I always struggled with ACID properties in DBMS.
I knew the full form.
Atomicity, Consistency, Isolation, Durability.
But honestly, none of it made sense to me back then.
I only understood it properly years later, while working on real systems at Cisco.
Let me explain it the way I finally understood it.
Imagine you have a savings account with 25,000 in it.
Your bank needs you to maintain a minimum balance of 5,000.
And you are transferring some amount to a friend.
A transfer has two steps.
Money goes out of your account.
Money goes into your friend’s account.
If the first happens and the second fails,
you end up losing money
and your friend still doesn’t receive anything.
That is an inconsistent and unfair state for the system.
Atomicity simply means
both steps must succeed together
or none of them should happen.
Consistency means
your transfer should not break the rules of the system.
If you try to send your full 25,000
your balance becomes zero
which violates the minimum 5,000 requirement.
So the system should not allow it.
Isolation is about timing.
Your account gets debited at one moment.
Your friend gets credited a little later.
If someone checks the balances in between,
they should not see half-done data.
They should either see the situation before the transfer
or after the transfer,
but never the messy middle.
Durability is the simple idea
that once the money has been transferred and committed,
it should never be lost
even if there is a crash or power failure.
That’s ACID.
The real version.
The version that finally clicked for me.
If you want me to simplify more concepts like this,
tell me which one I should take up next.
P.S. My new Data Engineering batch starts this Saturday. DM to know more!
#bigdata #sql #dataengineering
1 week ago | [YT] | 88