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copied!<p>Maybe the name <code>RAISE_APPLICATION_ERROR</code> is misleading for you. It will not pop up something onto your GUI. That you program yourself depending on what client you are using. Put you can use <code>RAISE_APPLICATION_ERROR</code> to create your own SQL errors on which you act upon.</p> <p>Example</p> <pre><code>-- a example table create table mytest (col_a number, col_b char(20)); -- a example trigger CREATE OR REPLACE TRIGGER mytest_before BEFORE UPDATE ON mytest FOR EACH ROW DECLARE BEGIN if :new.col_a < 0 then RAISE_APPLICATION_ERROR(-20299, 'negative value not allowed for column A'); end if; END; insert into mytest values (1,'hallo'); set serveroutput on DECLARE negative_value EXCEPTION; -- declare exception PRAGMA EXCEPTION_INIT (negative_value, -20299); -- assign error code to exception BEGIN update mytest set col_a = -1 where col_b = 'hallo'; EXCEPTION WHEN negative_value THEN -- handle exception -- do whatever you need to do to bring the error to the user DBMS_OUTPUT.PUT_LINE(TO_CHAR(SQLERRM(-20299))); END; / </code></pre> <p>The above will bring you the output in SQL*Plus or SQL Developer of that sort. </p> <pre><code>table MYTEST created. TRIGGER mytest_before compiled 1 rows inserted. anonymous block completed ORA-20299: negative value not allowed for column A ORA-06512: at "DEMO.MYTEST_BEFORE", line 4 ORA-04088: error during execution of trigger 'DEMO.MYTEST_BEFORE </code></pre> <p>Instead of DBMS_OUTPUT.PUT_LINE you can do whatever you need to do to show the user whatever you want him to show.</p>

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