Amazon QLDB Guide

Quantum Ledger Database (QLDB) explained

A guide to the AWS centralised ledger database

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Inspired by Alex DeBrie's DynamoDB Guide, which in turn was inspired by Craig Kerstein's Postgres Guide

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Amazon Quantum Ledger Database (QLDB)

is a fully managed ledger database that provides a transparent, immutable, and cryptographically verifiable transaction log owned by a central trusted authority. Amazon QLDB tracks each and every application data change and maintains a complete and verifiable history of changes over time

PartiQL - SQL Compatible interaction

You interact with QLDB using PartiQL, a SQL compatible query language familiar to engineers. This allows you to create tables, insert, update and delete records, and query data.
QLDB Guide

Journal First Architecture

Journal First

No record can be updated without going through the journal first

Committed Transactions

The journal contains only committed transactions

Materialized Views

Committed transactions are projected into materialized views that show both the current state, as well as the history of all revisions to a record.

Cryptographically Verified

As a transaction is committed, a SHA-256 hash is calculated and stored as part of the block. Each time a new block is added, the hash for that block is combined with the hash of the previous block (hash chaining). QLDB also builds a continuously updating Merkle tree of journal blocks. Using the digest and a proof object for a given document revision, you can cryptographically verify the specific document is in the same location in the journal and has not been altered in any way.