Managing Transactions for Sharded Data in Azure SQL Databases

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To manage transactional consistency across multiple Azure SQL databases with different sharding key values, you should implement elastic database transactions with horizontal partitioning (option A).

Option A: Elastic database transactions with horizontal partitioning Elastic database transactions with horizontal partitioning is a feature of Azure SQL Database that allows you to perform atomic transactions across multiple databases in a sharded database architecture. This approach allows you to partition your data horizontally across multiple databases while still maintaining transactional consistency.

This solution works by using a transaction coordinator, which is responsible for managing transactions across multiple shards. The coordinator uses a two-phase commit protocol to ensure that all the participating databases either commit or roll back the transaction. Elastic database transactions with horizontal partitioning provide a mechanism to ensure atomicity, consistency, isolation, and durability (ACID) properties across the entire transaction.

Option B: Distributed transactions coordinated by MSDTC Distributed transactions coordinated by MSDTC is a traditional approach to managing transactions across multiple databases. MSDTC is a Windows service that coordinates transactions across multiple resources such as databases, message queues, and file systems. However, this approach requires setting up MSDTC on all participating servers, which can be a complex and time-consuming process.

Option C: Server-coordinated transactions from .NET application Server-coordinated transactions from a .NET application is a feature of Azure SQL Database that allows you to perform transactions across multiple databases within the same logical server. This feature provides similar functionality to elastic database transactions with horizontal partitioning but is limited to a single logical server.

Option D: Elastic database transactions with vertical partitioning Elastic database transactions with vertical partitioning is another feature of Azure SQL Database that allows you to partition your data vertically across multiple databases. However, this approach is not suitable for managing transactions across multiple databases with different sharding key values.

In summary, to manage transactional consistency for changes across several different sharding key values, you should implement elastic database transactions with horizontal partitioning (option A). This approach provides a mechanism to ensure ACID properties across the entire transaction, allowing you to partition your data horizontally across multiple databases while still maintaining transactional consistency.