You need to recommend a solution for the error handling of USP_4. The solution must handle errors for nested stored procedures in the code for USP_4. What should you recommend?

Using @@ERROR in the nested stored procedures only checks the error status locally within those procedures but does not propagate the error back to USP_4, so the calling procedure remains unaware of the failure.

Checking @@ERROR in USP_4 alone will not capture errors that occur inside nested stored procedures, because those errors are scoped to the nested procedure's execution context and are not automatically visible to the caller.

When nested stored procedures encounter errors, they must use RAISERROR to explicitly surface those errors to the calling procedure. Without RAISERROR in the nested procedures, errors occurring within them are silently swallowed and never propagated to USP_4's error handling logic. This ensures that TRY/CATCH blocks or @@ERROR checks in USP_4 can actually detect and respond to failures originating in the nested calls.

Using RAISERROR only in USP_4 does nothing to surface errors that originate within the nested stored procedures, since those errors never reach USP_4 unless the nested procedures explicitly raise them first.