Amazon DynamoDB vs Azure SQL Database

Amazon DynamoDB is a serverless, managed NoSQL database for applications that need single-digit millisecond performance at any scale, according to AWS. Users do not provision or patch database servers, and tables can scale automatically, including to zero in on-demand mode. Primary keys and global or local secondary indexes provide ways to query data. Global tables support multi-Region, multi-active operation; AWS says they are designed for up to 99.999% availability. The database also supports native vector search for similarity searches and agent memory use cases. Data is encrypted in transit and at rest by default, and IAM policies can restrict access to specific items and attributes. Point-in-time recovery provides continuous, per-second backups and restoration within a configured period of 1 to 35 days. A free tier is listed with 25 WCUs, 25 RCUs, and 25 GB of storage per Region and payer account, among other limits. On-demand capacity is billed per request consumed; provisioned capacity is billed for specified capacity even if usage is lower.

Azure SQL Database is a cloud-native relational database service built on the SQL Server engine and delivered as a fully managed PaaS. Microsoft manages provisioning, patching, backups, monitoring, and high availability. The service supports standard T-SQL and can be accessed through the Azure portal, SQL Server Management Studio, Visual Studio Code's MSSQL extension, and compatible application frameworks. It supports native JSON and REST and GraphQL APIs through Data API builder. Hyperscale independently scales compute and storage and supports scale-out with up to 30 named replicas. For AI application development, it offers native vector search and connections to Azure OpenAI and Azure AI Search. It can connect to Azure Functions and replicate SQL data into Microsoft Fabric for near-real-time querying and analysis. Security and governance include a multilayered approach with Microsoft Defender for SQL; recovery features include disaster recovery and snapshot-based backups. The free offer allows up to 10 General Purpose databases per subscription, each with 100,000 vCore seconds, 32 GB of data, and 32 GB of backup storage monthly. Once limits are reached, a database can auto-pause or remain online with excess use billed at standard rates.