SQL Database Ledger, Is It Blockchain?

• Azure SQL Database Ledger is a high-end security feature that offers blockchain-like data verification for relational databases.
• The feature could be beneficial for supply chains or other systems where multiple parties need to verify database integrity.
• It requires extra computing resources, and unlike a blockchain, it centralizes data hosting and verification processes.

SQL Database Ledger is a new feature of the Azure SQL Database multitenant relational database management cloud service. It uses Azure SQL Database as a centralized hub to create and manage a shared ledger, which is a time-stamped data structure that contains the entire history of transactions for a system and cannot be altered by any one party in the system. SQL Database Ledger provides blockchain features like immutable storage and history verification that allow customers to add tamperproof controls to relational databases. It is easier to deploy than a blockchain; however, it relies on SQL Server components and a central hub for control and verification, which makes it more vulnerable to corruption than a decentralized blockchain environment. (See the sidebar “SQL Database Ledger Compared to Blockchain.”)