Now let's talk about Amazon QLDB,
which stands for Quantum Ledger Database.
So what is it?
A ledger is a book recording financial transactions
and so QLDB is going to be just to have a ledger
of financial transactions.
It's a fully managed database, it's serverless,
highly available, and has replication of data
across three availability T zones.
And it's used to review history of all the changes
made to your application data over time,
that's why it's called a ledger.
So it's an immutable system as well,
that means that once you write something to the database,
it can not be removed or modified.
And there is also a way to have a cryptographic signature
to make sure that indeed nothing has been removed.
So how does it work?
Well, there is behind the scenes a journal,
and so a journal has a sequence of modifications.
And so anytime a modification is made,
there is a cryptographic hash that is computed
which guarantees that nothing has been deleted or modified
and so this can be verified by anyone using the database.
So this is extremely helpful for financial transactions
because you wanna make sure that
obviously no financial transaction
is disappearing from your database
which makes QLDB a great ledger database in the cloud.
So you get two to three times better performance
than common ledger blockchain frameworks
and also you can manipulate data using SQL.
Now, as you'll see in the next lecture
there's also another database technologies
called Amazon Managed Blockchain.
But the difference between QLDB and Managed Blockchain
is that with QLDB, there is no concept of decentralization.
That means that there's just a central database
owned by Amazon that allows you to write this journal.
Okay.
And this is in line with many financial regulation rules.
So the difference between QLDB and Managed Blockchain
is that QLDB has a central authority component
and it's a ledger, whereas managed blockchain
is going to have a de-centralization component as well.
Okay.
So that's it, anytime you see financial transactions
and ledger, think QLDB.
I will see you in the next lecture.