🔹 Testing the API
✅ Save users:

curl -X POST "http://localhost:8080/users/save?userId=1&name=Alice"
curl -X POST "http://localhost:8080/users/save?userId=2&name=Bob"

✅ Retrieve users:

curl -X GET "http://localhost:8080/users/1"   # Should fetch from Shard 1
curl -X GET "http://localhost:8080/users/2"  # Should fetch from Shard 2

Important Points:

✅ Sharding distributes data across multiple Oracle databases for scalability.
✅ Spring Boot's AbstractRoutingDataSource helps dynamically switch between shards.
✅ Application-level sharding is useful when Oracle's built-in sharding isn't available.

Swagger URI:

http://localhost:8080/swagger-ui/index.html
http://localhost:8080/v3/api-docs

Additional Data Type Validations: