My PL/SQL procedure exception doesn't seem to work

Question

I have a database with continents and I wanted to create a procedure that added a new continent to the database, with exceptions. I tried executing the procedure inside my package GEST_GEO by creating an already existing continent (Asia) and my exception was not raised. Does anyone have any idea that to why it doesn't work ? (nom is name)

Here is my code :

CREATE OR REPLACE PACKAGE GEST_GEO AS
Procedure ADDCONTINENT(pnom continent.nom%TYPE, psuperficie continent.superficie%TYPE);
END GEST_GEO;
/

CREATE OR REPLACE PACKAGE BODY GEST_GEO AS

-- ADDCONTINENT

Procedure ADDCONTINENT(pnom CONTINENT.NOM%TYPE, psuperficie CONTINENT.SUPERFICIE%TYPE) IS
BEGIN
    INSERT INTO CONTINENT VALUES (pnom, psuperficie);
COMMIT;
EXCEPTION
    WHEN DUP_VAL_ON_INDEX THEN DBMS_OUTPUT.PUT_LINE('The continent already exists');
    WHEN OTHERS THEN DBMS_OUTPUT.PUT_LINE(SQLCODE || '–' || SQLERRM);

END ADDCONTINENT;
END GEST_GEO;
/


execute GEST_GEO.ADDCONTINENT('Asia',99380);

When executing it it just tells me PL/SQL procedure successfully completed

Thank you

Answer 1

DUP_VAL_ON_INDEX presumes that there's a primary or unique key, or unique index enforced on that column. If there's none, Oracle doesn't know that there's anything "duplicated" so it inserts a row.

Therefore, create something of previously mentioned (keys/indexes).

---

Here's an example: table first (note the primary key constraint in line #2):

SQL> create table continent
  2    (nom         varchar2(30) constraint pk_cont primary key,
  3     superficie  number
  4    );

Table created.

Procedure: note

• line #5 - always include target column names in INSERT statement
• exception handler section: don't output the message - unless tool you use supports it, buffer's contents won't be visible to anyone. RAISE the error instead
• don't commit within the procedure; let the caller decide whether to commit or not

So:

SQL> create or replace procedure addcontinent
  2    (pnom continent.nom%type, psuperficie continent.superficie%type)
  3  is
  4  begin
  5    insert into continent (nom, superficie) values (pnom, psuperficie);
  6  exception
  7    when dup_val_on_index then
  8      raise_application_error(-20001, 'The continent already exists');
  9    when others then
 10      raise;
 11  end addcontinent;
 12  /

Procedure created.

Testing:

SQL> exec addcontinent('Asia', 99380);

PL/SQL procedure successfully completed.

SQL> exec addcontinent('Asia', 99380);
BEGIN addcontinent('Asia', 99380); END;

*
ERROR at line 1:
ORA-20001: The continent already exists
ORA-06512: at "SCOTT.ADDCONTINENT", line 8
ORA-06512: at line 1


SQL> select * from continent;

NOM                            SUPERFICIE
------------------------------ ----------
Asia                                99380

SQL>