Using raise_application_error - user-defined exceptions, PL-SQL Programming

Assignment Help:

Using raise_application_error

The Package DBMS_STANDARD that is supplied with Oracle gives language facilities that help your application to interact with Oracle. For illustration, the procedure raise_application_error lets you issue user-defined error messages from the stored subprograms. In that way, you can report errors to your application and avoid returning unhandled exceptions. To call the raise_application_error, use the syntax shown below:

raise_application_error(error_number, message[, {TRUE | FALSE}]);

Where error_number is a negative integer in the range of -20000... -20999 and message is a character string of upto 2048 bytes long. When the optional third parameter is TRUE, then the error is placed on the stack of earlier errors. And If the parameter is FALSE (the default), the error replaces all earlier errors. The Package DBMS_ STANDARD is an extension of the package STANDARD, so you do not require qualifying the references to its contents.

An application can only call the raise_application_error from an executing stored subprogram (or method). Whenever called, raise_application_error ends the subprogram and returns a user-defined error number and message to the application. Error number and the message can be trapped such as any Oracle error.

In the example below, you call the raise_application_error if an employee's salary is missing:

CREATE PROCEDURE raise_salary (emp_id NUMBER, amount NUMBER) AS

curr_sal NUMBER;

BEGIN

SELECT sal INTO curr_sal FROM emp WHERE empno = emp_id;

IF curr_sal IS NULL THEN

/* Issue user-defined error message. */

raise_application_error(-20101, 'Salary is missing');

ELSE

UPDATE emp SET sal = curr_sal + amount WHERE empno = emp_id;

END IF;

END raise_salary;

The calling applications get a PL/SQL exception that can process using the error-reporting functions SQLCODE and SQLERRM in an OTHERS handler. It can also use the pragma EXCEPTION_INIT to map precise error numbers returned by the raise_application_error to exceptions of its own, as shown below:

EXEC SQL EXECUTE

/* Execute embedded PL/SQL block using host

variables my_emp_id and my_amount, which were

assigned values in the host environment. */

DECLARE

...

null_salary EXCEPTION;

/* Map error number returned by raise_application_error

to user-defined exception. */

PRAGMA EXCEPTION_INIT(null_salary, -20101);

BEGIN

...

raise_salary(:my_emp_id, :my_amount);

EXCEPTION

WHEN null_salary THEN

INSERT INTO emp_audit VALUES (:my_emp_id, ...);

...

END;

END-EXEC;

This method allows the calling application to handle error conditions in the specific exception handlers.


Related Discussions:- Using raise_application_error - user-defined exceptions

Using subqueries, Using Subqueries A subquery is a query (typically ...

Using Subqueries A subquery is a query (typically enclosed by parentheses) that appears within another SQL data manipulation statement. If evaluated, the subquery gives a va

Between and not between operator in sql, BETWEEN and NOT BETWEEN Operator i...

BETWEEN and NOT BETWEEN Operator in SQL Example: Restricting exam marks to between 0 and 100 CREATE ASSERTION Marks_between_0_and_100 CHECK (NOT EXISTS (SELECT * FROM

Using aliases-declarations in sql, Using Aliases The Select-list items f...

Using Aliases The Select-list items fetched from a cursor related with the %ROWTYPE should have simple names or, if they are expressions, should have aliases. In the example bel

Solve the business problems using sql, Use the MASCOT tables CREDITRS, PORD...

Use the MASCOT tables CREDITRS, PORDS and PAYMENTS to write SQL queries to solve the following business problems. These tables / data are available to you via the USQ Oracle server

Sql database, SQL Database: So, an SQL database is one whose symbols a...

SQL Database: So, an SQL database is one whose symbols are organized into a collection of tables. Now, shows an SQL table as the current value of an SQL variable, ENROLMENT, b

Use triggers to maintain referential integrity, At times, Brewbean's has ch...

At times, Brewbean's has changed the id number for existing products. In the past, they have had to add a new product row with the new id to the BB_PRODUCT table, modify all the co

Bulk binds advantages, Bulk Binds advantages In the Embedded Oracle RDB...

Bulk Binds advantages In the Embedded Oracle RDBMS, the PL/SQL engines accept any valid PL/SQL subprogram or block. As the figure shows, the PL/SQL engine executes all procedur

Declarations in sql-pl/sql, Declarations in SQL Your program stores value...

Declarations in SQL Your program stores values in the variables and constants. As the program executes, the value of the variables can change, but the values constants cannot.

Product-specific packages in pl/sql, Product-specific Packages The Ora...

Product-specific Packages The Oracle and different Oracle tools are supplied with the product-specific packages which help you to build the PL/SQL-based applications. For illu

Operators on tables and rows, Operators on Tables and Rows Row Extrac...

Operators on Tables and Rows Row Extraction TUPLE FROM r, SQL has row subqueries. These are just like scalar subqueries except that they may specify more than one column.

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd