Stored Function in Oracle not Inserting Values into the desired table - sql

Question

Here is my Code given below. I am trying to add 5 parameters which the function takes into the table Employee. But I am not successful in doing it and have tried a lot of things.
Error
ORA-01858: a non-numeric character was found where a numeric was
expected ORA-06512: at "xxxxxxx.A1SF_ADDEMP", line 14
01858. 00000 - "a non-numeric character was found where a numeric was expected"
*Cause: The input data to be converted using a date format model was
incorrect. The input data did not contain a number where a number was
required by the format model.
*Action: Fix the input data or the date format model to make sure the
elements match in number and type. Then retry the operation.
Plus how do I test a Stored function that has a Insert/Update or Delete Statement in it?
Execution Statement
Select A1SF_ADDEMP('Adesh', '33', 'M', 8000, '26/03/1990')
From dual;
Code
CREATE OR REPLACE Function A1SF_ADDEMP
(pEmpName In Varchar2,
pTaxFileNo In Varchar2,
pGender In Varchar2,
pSalary In Number,
pBirthdate In Varchar2
) Return Varchar2
Is
tEmpId Number(38,0);
tBirthDate Date;
BEGIN
tEmpId := A1Seq_Emp.nextval;
tBirthdate := to_date('pBirthdate','dd/mm/yyyy');
Insert Into Employee(EmpId, EmpName, TaxFileNo, Gender, Salary, Birthdate)
Values (tEmpId, pEmpName, pTaxFileNo, pGender, pSalary, tBirthdate);
Commit;
Return null;
END;

Answer 1

Firstly you cannot call a function with DML in it in a select statement. You have to assign the output to a variable in a PL/SQL block, something like:
declare
l_output number;
begin
l_output := my_function(variable1, variable2);
end;
It's bad practice to do DML in a function; partly because it causes the errors you're coming across. You should use a procedure as detailed below. The other reason for this is that you're as always returning null there's no need to return anything at all!
create or replace procedure my_procedure ( <variables> ) is
begin
insert into employees( <columns> )
values ( <values > );
end;
The specific reason for your error is this line:
tBirthdate := to_date('pBirthdate','dd/mm/yyyy');
pBirthdate is already a string; by putting a ' around it you're passing the string 'pBirthdate' to the function to_date and Oracle can't convert this string into a day, month or year so it's failing.
You should write this as:
tBirthdate := to_date(pBirthdate,'dd/mm/yyyy');
You also don't need to specify number(38,0), you can just write number instead.
It is possible to return a value from a procedure using the out keyword. If we assume that you want to return empid you could write is as something like this:
create or replace procedure A1SF_ADDEMP (
pEmpName in varchar2
, pTaxFileNo in varchar2
, pGender in varchar2
, pSalary in number
, pBirthdate in varchar2
, pEmpid out number
) return varchar2 is
begin
pempid := A1Seq_Emp.nextval;
Insert Into Employee(EmpId, EmpName, TaxFileNo, Gender, Salary, Birthdate)
Values ( pEmpId, pEmpName, pTaxFileNo, pGender
, pSalary, to_date(pBirthdate,'dd/mm/yyyy');
end;
To just execute the procedure call it like this:
begin
A1SF_ADDEMP( EmpName, TaxFileNo, Gender
, Salary, Birthdate);
commit;
end;
If you want to return the empid then you can call it like this:
declare
l_empid number;
begin
l_empid := A1SF_ADDEMP( EmpName, TaxFileNo, Gender
, Salary, Birthdate);
commit;
end;
Notice how I've moved the commit to the highest level, this is to avoid committing stuff in every procedure when you might have more things you need to do.
Incidentally, if you're using Oracle 11g then there's no need to assign the value A1Seq_Emp.nextval to a variable. You can just insert it directly into the table in the values list. You, of course won't be able to return it, but you could return A1Seq_Emp.curval, as long as there's nothing else getting values from the sequence.

Answer 2

You should use a procedure (instead of a function) if you are not returning any values.
If you look at the line mentioned in the error message you can spot your error:
tBirthdate := to_date('pBirthdate','dd/mm/yyyy');
You are passing the string literal 'pBirthdate' to the to_date() call. But you want to pass the parameter, so it should be
tBirthdate := to_date(pBirthdate,'dd/mm/yyyy');
(note the missing single quotes arount pBirthdate).
So as a procedure the whole thing would look like this:
CREATE OR REPLACE PROCEDURE A1SF_ADDEMP
(pEmpName In Varchar2,
pTaxFileNo In Varchar2,
pGender In Varchar2,
pSalary In Number,
pBirthdate In Varchar2
)
IS
BEGIN
Insert Into Employee(EmpId, EmpName, TaxFileNo, Gender, Salary, Birthdate)
Values (A1Seq_Emp.nextval, pEmpName, pTaxFileNo, pGender, pSalary, to_date(pBirthdate,'dd/mm/yyyy'));
Commit;
END;
To run it:
execute A1SF_ADDEMP('Adesh', '33', 'M', 8000, '26/03/1990');

Answer 3

In your situation you need to use procedure with out parameter where your out param is your returning param that contains your desirable value. This is I think best practice in this situation when you want to use DML in select statement.
Second way to do it but its not a good practice is to use one function like yours but before return a value you need to use if statement to check what is the value and if value is what you desire to call in this if statement PRAGMA AUTONOMOUS_TRANSACTION procedure which will do your DML independently of function calling to it. For more information about pragma transactions your can read here:
http://docs.oracle.com/cd/B19306_01/appdev.102/b14261/autonotransaction_pragma.htm
Best Regards and hope I was helpful