How is the usage of oracle exception?

In Oracle databases, exception handling is a mechanism used to handle runtime errors. When exceptions or errors occur during program execution, exception handling can be used to catch and manage these exceptions, ensuring that the program does not unexpectedly terminate.

Exception handling can be implemented using the following statements and keywords:

1. TRY-CATCH statement: The TRY block contains the code that may throw an exception, and the CATCH block is used to capture and handle the exception.
2. BEGIN
   — Code that may cause an exception
   EXCEPTION
   WHEN exception_name THEN
   — Code to handle the exception
   END;
3. RAISE EXCEPTION statement: Used to manually trigger an exception.
4. If the condition is met, an exception named exception_name is raised.
5. EXCEPTION INITIALIZATION statement: Used to assign a value to an exception variable during declaration.
6. Declare an exception variable and initialize it with the error code -20001 before entering the code block.
7. EXCEPTION WHEN OTHERS statement: used to handle exceptions that are not explicitly handled.
8. BEGIN
   …
   EXCEPTION
   WHEN OTHERS THEN
   — Handle exceptions that are not explicitly handled
   END;

By utilizing these exceptional handling mechanisms, one can effectively manage runtime errors, enhancing the robustness and reliability of the program.