oracle exception

Oracle exception refers to the error or exception that occurs during the execution of an Oracle database operation. When an error occurs, Oracle throws an exception, which can be caught and handled by the application.

Oracle provides a set of predefined exceptions that cover common errors, such as invalid data, constraints violations, and system-related issues. These predefined exceptions have names like NO_DATA_FOUND, DUP_VAL_ON_INDEX, and TOO_MANY_ROWS.

In addition to the predefined exceptions, Oracle also allows users to declare and define their custom exceptions using the EXCEPTION keyword. Custom exceptions can be raised explicitly in the PL/SQL code when specific conditions are met.

To handle exceptions in Oracle, you can use the EXCEPTION block in PL/SQL. Inside the block, you can catch specific exceptions using the WHEN clause and perform appropriate actions to handle the error, such as logging the error, displaying a message, or rolling back the transaction.

Here's an example of handling an exception in PL/SQL:

BEGIN
  -- Code that may cause an exception
EXCEPTION
  WHEN NO_DATA_FOUND THEN
    -- Code to handle the exception
  WHEN DUP_VAL_ON_INDEX THEN
    -- Code to handle the exception
  WHEN OTHERS THEN
    -- Code to handle all other exceptions
END;

By catching and handling exceptions properly, you can ensure that your application gracefully handles errors and provides meaningful feedback to users.