Jun 03, 2021

AWS Quantum Ledger Database


Amazon 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.

About QLDB

Quantum Ledger Database(QLDB) is a No-SQL(Semi-SQL & Semi-NoSQL) Append-only database that provides an immutable, transparent, and cryptographically verifiable transaction log ‎owned by a central authority. Since it is a No-SQL database, It has the ability to store a lot of semi-unstructured data using a document-oriented data model. Moreover, it Uses SQL like data structure(Tables and Rows) and a language(PartiQL). So, it can leverage current SQL developers to offer robust ways to query and manage data.

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Traditional Databases vs AWS QLDB

Any other traditional databases (SQL and No-SQL) store data in the form of a table or JSON document model. Within these traditional databases, data can be modified by anyone who is in control of the database itself results in data conflicts and manipulations. These databases don't keep track of document history and only store the current state of the document. So, these databases cannot provide audit trials out of the box. As all of these databases do not have automatic data encryption so the data files are at risk of being read or modified by hackers directly. While most of these databases cannot work with cryptography, so it is not possible to immute the data and cannot prove who modified what.

AWS is always at the front when it comes to blockchain technology or any technology in general. Amazon, itself being a giant knows the importance of data among the businesses. It introduced QLDB in 2018 along with Amazon Managed Blockchain.

Key Features of QLDB:

Immutability & Transparency

Amazon QLDB has a built-in immutable journal that stores an accurate and sequenced entry of every data change. The journal is append-only, meaning that data can only be added to a journal and it cannot be overwritten or deleted.

Audit Logs & History

With Amazon QLDB, you can access the entire change history of your application’s data. You can query a summary of historical changes, and also specific details related to transaction history and provides Audit trails out of the box.


Amazon QLDB uses cryptography to create a concise summary of your change in history. This secure summary, commonly known as a digest, is generated using a cryptographic hash function (SHA-256). The digest acts as proof of your data’s change history, allowing you to look back and verify the integrity of your data changes.

Highly Scalable

With Amazon QLDB, you don’t have to worry about provisioning capacity or configuring read and write limits. You create a ledger, define your tables, and QLDB automatically scales to support the demands of your application.

Read more here - https://medium.com/devopsinternationalbv/what-is-this-quantum-ledger-database-that-im-keep-hearing-about-a3c16c35c799