Exceptions:

This lesson deals with handling run-time errors which are raised due to several reasons and to provide an understandable user-friendly message. For Creating and showing user-defined error messages are also dealt with.

• Introduction to Exception
• Predefined exception
• List of Predefined exceptions
• Handling user-defined exceptions
• Using Raise_application_error
• Usage of SQLCODE and SQLERRM

Exceptions  are  an  identifier  in  PL/SQL, raised in during  the execution  of  a  block  which terminates its main body of actions. The block always terminates when PL/SQL raises an exception but you denote an exception handler to perform last actions.

Two techniques for raising an exception are given below:

1. An oracle error occurs and the related exception is raised automatically. For instance, if the error ORA-04103 occurs when no rows are retrieved from the database in a select statement and then PL/SQL raises the exception NO_DATA_FOUND.

2. You raise an exception explicitly through issuing the RAISE statement inside the block. The exception being raised might be either user predefined or defined.