Question

I want to create a simple procedure that when passed a primary key will delete a record from a table.

I have read this thread about SQL%NOTFOUND. I think that the solution for that problem is to use a function that checks that the parameter passed is a primary key of that table and returns a boolean. I’m sure that there are more things to look out for here though.

What other problems or specific exceptions should I look for?

Here is the basic template for my procedure:

create or replace procedure delete_employee
  ( employee_id_i in employees.employee_id%type) is
begin
  if valid_employee(employee_id_i) then
    delete from employees where employee_id = employee_id_i;
  end if;
exception
  when others then
    log_error_proc(dbms_utility.format_error_stack(),
                   dbms_utility.format_error_backtrace());
end delete_employees;

Answer 1

You should use the ROWCOUNT attribute of the implicit cursor instead. This will return the number of affected rows from the DELETE statement, and saves you from having to query the table in your valid_employee function.

create or replace procedure delete_employee
  ( employee_id_i in employees.employee_id%type) is
begin
  delete from employees where employee_id = employee_id_i;
  if SQL%ROWCOUNT == 0 then
    null; -- throw exception, write log message, return something...
  end if;
exception
  when others then
    log_error_proc(dbms_utility.format_error_stack(),
                   dbms_utility.format_error_backtrace());
end delete_employees;