A team is moving an application from Azure Table Storage to the Cosmos DB Table API. It wants to keep its existing Azure Tables SDK calls unchanged. What change to the application is required?
Show answer and explanation
Answer: A
The Cosmos DB Table API implements the Azure Table Storage protocol, so applications that use the Azure Tables SDK can keep their existing calls. The main code-level change is the connection string, which now points to the Cosmos DB account's table endpoint. Moving the existing data is a separate step. Cosmos DB-specific capabilities, such as configurable throughput, can be adopted later without changing the calls.
Why the other options are wrong
- B. Rewriting against the SQL API SDK is unnecessary, because the Table API accepts the same Table SDK calls. It adds effort without meeting any requirement in this scenario.
- C. Exporting and rebuilding around Cosmos-only features goes well beyond what the migration needs. The application can keep its current data access code.
- D. Partition design can be revisited later, and redesigning every table is not required to keep the existing SDK working. Deriving keys from the row id would also spread each entity into its own partition, which is a poor choice.