Using Named System Exceptions in Oracle

This Oracle tutorial explains how to use Named System Exceptions in Oracle/PLSQL with syntax and examples.

What is a named system exception in Oracle?

Named machine exceptions are exceptions that have been given names by way of PL/SQL. They are named in the STANDARD package in PL/SQL and do not want to be defined via the programmer.

Oracle has a popular set of exceptions already named as follows:

Oracle Exception Name Oracle Error Explanation DUP_VAL_ON_INDEX ORA-00001 You tried to execute an INSERT or UPDATE assertion that has created a replica cost in a subject confined by using a special index. TIMEOUT_ON_RESOURCE ORA-00051 You have been ready for a resource and you timed out. TRANSACTION_BACKED_OUT ORA-00061 The far off component of a transaction has rolled back. INVALID_CURSOR ORA-01001 You tried to reference a cursor that does no longer but exist. This can also have came about because you’ve got executed a FETCH cursor or CLOSE cursor before OPENing the cursor. NOT_LOGGED_ON ORA-01012 You tried to execute a call to Oracle earlier than logging in. LOGIN_DENIED ORA-01017 You tried to log into Oracle with an invalid username/password combination. NO_DATA_FOUND ORA-01403 You tried one of the following: You carried out a SELECT INTO assertion and no rows were returned. You referenced an uninitialized row in a table. You study past the cease of file with the UTL_FILE package. TOO_MANY_ROWS ORA-01422 You tried to execute a SELECT INTO declaration and extra than one row used to be returned. ZERO_DIVIDE ORA-01476 You tried to divide a wide variety by zero. INVALID_NUMBER ORA-01722 You tried to execute a SQL announcement that tried to convert a string to a number, however it was unsuccessful. STORAGE_ERROR ORA-06500 You ran out of memory or memory used to be corrupted. PROGRAM_ERROR ORA-06501 This is a typical “Contact Oracle support” message due to the fact an internal trouble was once encountered. VALUE_ERROR ORA-06502 You tried to perform an operation and there was once a error on a conversion, truncation, or invalid constraining of numeric or personality data. CURSOR_ALREADY_OPEN ORA-06511 You tried to open a cursor that is already open.

Syntax

We will take a appear at the syntax for Named System Exceptions in each methods and functions.

Syntax for Procedures

The syntax for the Named System Exception in a method is:

CREATE [OR REPLACE] PROCEDURE procedure_name
   [ (parameter [,parameter]) ]
IS
   [declaration_section]

BEGIN
   executable_section

EXCEPTION
   WHEN exception_name1 THEN
      [statements]

   WHEN exception_name2 THEN
      [statements]

   WHEN exception_name_n THEN
      [statements]

   WHEN OTHERS THEN
      [statements]

END [procedure_name];

Syntax for Functions

The syntax for the Named System Exception in a characteristic is:

CREATE [OR REPLACE] FUNCTION function_name
   [ (parameter [,parameter]) ]
   RETURN return_datatype
IS | AS
   [declaration_section]

BEGIN
   executable_section

EXCEPTION
   WHEN exception_name1 THEN
      [statements]

   WHEN exception_name2 THEN
      [statements]

   WHEN exception_name_n THEN
      [statements]

   WHEN OTHERS THEN
      [statements]

END [function_name];

Example

Here is an instance of a system that uses a Named System Exception:

CREATE OR REPLACE PROCEDURE add_new_supplier
   (supplier_id_in IN NUMBER, supplier_name_in IN VARCHAR2)
IS

BEGIN
   INSERT INTO suppliers (supplier_id, supplier_name )
   VALUES ( supplier_id_in, supplier_name_in );

EXCEPTION
   WHEN DUP_VAL_ON_INDEX THEN
      raise_application_error (-20001,'You have tried to insert a duplicate supplier_id.');

   WHEN OTHERS THEN
      raise_application_error (-20002,'An error has occurred inserting a supplier.');

END;

In this example, we are trapping the Named System Exception known as DUP_VAL_ON_INDEX. We are also the usage of the WHEN OTHERS clause to entice all remaining exceptions.