VARCHAR2 Becomes Numeric by passing as parameter to a function - oracle

Question

I'm working on a school work and I have an error in my code.
I have created a PLSQL package:
create or replace
PACKAGE GestionProjets AS
TYPE Signaletique IS TABLE OF EMPLOYES%ROWTYPE INDEX BY BINARY_INTEGER;
TYPE TableNomDep IS TABLE OF VARCHAR2(40);
PROCEDURE AjouterProjets(ProjetRecord IN PROJETS%ROWTYPE);
PROCEDURE SupprimerProjet(DelNumPro IN PROJETS.numpro%TYPE);
--PROCEDURE ModifierProjet(newRecord IN PROJETS%ROWTYPE, oldRecord IN PROJETS%ROWTYPE);
FUNCTION ListerEmployes(dep1 IN DEPARTEMENTS.Nomdep%TYPE, dep2 IN DEPARTEMENTS.Nomdep%TYPE) RETURN Signaletique;
END GestionProjets;
That's the body of the function where I have an error:
FUNCTION ListerEmployes(dep1 IN DEPARTEMENTS.Nomdep%TYPE, dep2 IN DEPARTEMENTS.Nomdep%TYPE) RETURN Signaletique AS
nomDeps TableNomDep;
SigTable Signaletique;
EXWrongDep1 EXCEPTION;
EXWrongDep2 EXCEPTION;
BEGIN
SELECT Nomdep
BULK COLLECT INTO nomDeps
FROM DEPARTEMENTS;
-- test if dep 1 est un parametre valide
IF NOT nomDeps.exists(dep1) THEN
RAISE EXWrongDep1;
END IF;
-- test if dep 2 est un parametre valide
IF NOT nomDeps.exists(dep2) THEN
RAISE EXWrongDep2;
END IF;
EXCEPTION
WHEN EXWrongDep1 THEN
RAISE_APPLICATION_ERROR(-20008, 'MAUVAIS PARAMETRE: ' || dep1 || ' N EXISTE PAS!');
WHEN EXWrongDep2 THEN
RAISE_APPLICATION_ERROR(-20008, 'MAUVAIS PARAMETRE: ' || dep2 || ' N EXISTE PAS!');
WHEN OTHERS THEN
RAISE_APPLICATION_ERROR (-20007, 'ERREUR INCONNU: ' || SQLCODE || ' - ' || SQLERRM);
END ListerEmployes;
When I try to execute the function, i get this error message:
DECLARE
tabel gestionprojets.Signaletique;
BEGIN
tabel := gestionprojets.listeremployes('sdsd','sdsd');
END;
ORA-20007: ERREUR INCONNU: -6502 - ORA-06502: PL/SQL: numeric or value error: character to number conversion error
ORA-06512: at "EDGE.GESTIONPROJETS", line 108
ORA-06512: at line 4
I don't understand why I get this error message. The type of the Nomdep column is VARCHAR2(40).

Answer 1

I suspect the problem is that the table type is indexed by BINARY_INTEGER. When the .EXISTS calls are executed they're passed either dep1 or dep2 as the index for the table, and thus PL/SQL tries to convert the VARCHAR2(40) parameter to a BINARY_INTEGER. Since these input parameters are both non-numeric character strings ('sdsd') the conversion fails.
This code might run faster if, instead of reading the entire DEPARTEMENTS table into memory each time ListerEmployes is called, it was rewritten as
FUNCTION ListerEmployes(dep1 IN DEPARTEMENTS.Nomdep%TYPE, dep2 IN DEPARTEMENTS.Nomdep%TYPE) RETURN Signaletique
AS
strNomdep DEPARTEMENTS.Nomdp%TYPE;
BEGIN
-- test if dep 1 est un parametre valide
BEGIN
SELECT NOMDEP
INTO strNomdep
FROM DEPARTEMENTS
WHERE NOMDEP = dep1;
EXCEPTION
WHEN NO_DATA_FOUND THEN
RAISE_APPLICATION_ERROR(-20008, 'MAUVAIS PARAMETRE: ' || dep1 || ' N EXISTE PAS!');
END;
-- test if dep 2 est un parametre valide
BEGIN
SELECT NOMDEP
INTO strNomdep
FROM DEPARTEMENTS
WHERE NOMDEP = dep2;
EXCEPTION
WHEN NO_DATA_FOUND THEN
RAISE_APPLICATION_ERROR(-20008, 'MAUVAIS PARAMETRE: ' || dep2 || ' N EXISTE PAS!');
END;
EXCEPTION
WHEN OTHERS THEN
RAISE_APPLICATION_ERROR (-20007, 'ERREUR INCONNU: ' || SQLCODE || ' - ' || SQLERRM);
END ListerEmployes;
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