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    Exception Handling: PL/SQL Exceptions Consist Following Three

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    Nikita Kharade
    In PL/SQL, exceptions are errors or warnings that occur during program execution. There are two types of exceptions: predefined exceptions, which are raised implicitly for Oracle errors, and user-defined exceptions, which are declared and raised explicitly by the programmer. When an exception is raised, normal execution stops and control transfers to the exception handling part of the PL/SQL block, allowing the programmer to specify statements to execute in response to the exception.

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    Exception Handling: PL/SQL Exceptions Consist Following Three

    Uploaded by

    Nikita Kharade
    194 views3 pages
    In PL/SQL, exceptions are errors or warnings that occur during program execution. There are two types of exceptions: predefined exceptions, which are raised implicitly for Oracle errors, and user-defined exceptions, which are declared and raised explicitly by the programmer. When an exception is raised, normal execution stops and control transfers to the exception handling part of the PL/SQL block, allowing the programmer to specify statements to execute in response to the exception.

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    Exception handling

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    Exception Handling

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    In PL/SQL, exceptions are errors or warnings that occur during program execution. There are two types of exceptions: predefined exceptions, which are raised implicitly for Oracle errors, and user-defined exceptions, which are declared and raised explicitly by the programmer. When an exception is raised, normal execution stops and control transfers to the exception handling part of the PL/SQL block, allowing the programmer to specify statements to execute in response to the exception.

    Copyright:

    © All Rights Reserved
    194 views3 pages

    Exception Handling: PL/SQL Exceptions Consist Following Three

    Uploaded by

    Nikita Kharade
    In PL/SQL, exceptions are errors or warnings that occur during program execution. There are two types of exceptions: predefined exceptions, which are raised implicitly for Oracle errors, and user-defined exceptions, which are declared and raised explicitly by the programmer. When an exception is raised, normal execution stops and control transfers to the exception handling part of the PL/SQL block, allowing the programmer to specify statements to execute in response to the exception.

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    of 3

    Exception Handling

     
    In PL/SQL , a warning or error condition is called an exception, which arises during program 
    execution. Run­time errors or exception arise from design faults, coding mistakes, hardware 
    failure and many other sources. When an error occurs, an exception is raised, i.e. the normal 
    execution stops and the control transfers to the exception handling part of the PL/SQL block. 
    Exceptions are the identifiers in PL/SQL which may be raised during the 
    execution of a block to terminate its main body of actions. A block will always terminate when 
    an exception is raised, but you may specify an ‘Exception Handler’ to perform final actions 
    before the block terminates. 
     
    PL/SQL exceptions consist following three,
    1. Exception Type
    2. Error Code
    3. Error Message
    TYPES OF EXCEPTION
    Exceptions can be of two types :-
    (1) Predefined Exception
    (2) User-defined Exception

    PL/SQL Predefined Exception :-


    They are internally defined by runtime system. It is raised implicitly whenever PL/SQL
    program violates an ORACLE rule or exceeds a system-dependent limit. Every Oracle
    error has a number, but exceptions must be handled by name. So, PL/SQL
    predefined some common ORACLE errors as exceptions.
    For example, if you try to divide a number by zero then PL/SQL raises an exception 
    called ZERO_DIVIDE and if SELECT can not find a record then PL/SQL raises exception 
    NO_DATA_FOUND. 
     
    How to handle exception ?? 
    When PL/SQL raises a predefined exception, the program is aborted by displaying error 
    message. But if program is to handle exception raised by PL/SQL then we have to use 
    Exception handling part of the PL/SQL block. 
    Exception handling part is used to specify the statements to be executed when 
    an exception occurs. Control is transferred to exception handling part whenever an 
    exception occurs. After the exception handler is executed, control is transferred to next 
    statement in the enclosing block. 
     
    Syntax :­ 
    WHEN <exception­identifier> THEN <action>; 
    Where <actions> may be one or more PL/SQL or SQL statements, each
    terminated by semi-colons.
     
    Example :­ 
     
    DECLARE 
    N NUMBER; 
    BEGIN 
    N:=10/0; 
    EXCEPTION 
    WHEN ZERO_DIVIDE THEN 
    DBMS_OUTPUT.PUT_LINE (‘ ZERO DIVIDE ERROR’ ); 
    END; 
    / 
     
    PL/SQL User Defined Exception
    PL/SQL user defined exception to make your own exception. PL/SQL give you control to
    make your own exception base on oracle rules. User define exception must be declare
    yourself and RAISE statement to raise explicitly.

    How to Define Exception


    (1) Declare exception :-​
    You must have to declare user define exception name in
    DECLARE block.

    user_define_exception_name EXCEPTION​
    ; 

    (2) RAISE exception :- ​


    RAISE statement to raised defined exception name and control
    transfer to a EXCEPTION block.

    RAISE user_define_exception_name​
    ; 

    (3) Handling an Exception Condition :- ​ In PL/SQL EXCEPTION block add WHEN


    condition to implement user-defined action.
     

    BEGIN 

    ­­­­­­­­­­­­ 

    ­­­­­­­­­­­­ 

    EXCEPTION 

    WHEN user_define_exception_name THEN 
    User­defined statements (action) will be taken; 

       END; 

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