Question

I’ve created regular function. It has been created successfully. But when I run it with

select reg('awlad','01968688680','545466455','12345') from dual

It gives me this error:

ORA-14551: cannot perform a DML operation inside a query

How can I solve this?

CREATE OR REPLACE FUNCTION reg(
name in varchar2,
cellNo in varchar2,
voterId in varchar2,
pass in varchar2
)
RETURN NUMBER
IS 
succ NUMBER;
BEGIN 
      succ:=0;
      insert into logInfo values(loginfo_seq.nextval,cellNo,pass,0);
      succ:=1;
      insert into passInfo values(name,cellNo,voterId);
      succ:=2;
      RETURN succ;
END;

Answer 1

A function is supposed to compute and return a result, not change the state of the database. If you want to do DML in a function (i.e. if you want to insert rows into tables), you cannot call that function in a SELECT statement since a SELECT statement cannot change the state of the database. In general, you’d be better off creating this sort of thing as a stored procedure rather than a stored function.

You can call this function from a PL/SQL block just as you would call a stored procedure

DECLARE
  l_success_code NUMBER;
BEGIN
  l_success_code := reg('awlad','01968688680','545466455','12345');
END;

If you want to create this as a procedure

CREATE OR REPLACE PROCEDURE reg( name in varchar2, 
                                 cellNo in varchar2, 
                                 voterId in varchar2, 
                                 pass in varchar2, 
                                 succ out NUMBER ) 
AS 
BEGIN 
  succ:=0; 
  insert into logInfo values(loginfo_seq.nextval,cellNo,pass,0); 
  insert into passInfo values(name,cellNo,voterId); 
  succ:=1; 
END;

then you’d need to call the procedure by passing in the OUT parameter

DECLARE
  l_success_code NUMBER;
BEGIN
  reg('awlad','01968688680','545466455','12345', l_success_code);
END;