G-4385
Warning
Never use a cursor for loop to check whether a cursor returns data.
Reason
You might process more data than required, which leads to bad performance.
Example
Non-Compliant Example
declare
l_employee_found boolean := false;
cursor c_employees is
select employee_id,last_name
from employees;
begin
<<check_employees>>
for r_employee in c_employees
loop
l_employee_found := true;
end loop check_employees;
if l_employee_found then
null; -- some processing;
end if;
end;
/Issues
| Line | Column | Message |
|---|---|---|
| 8 | 4 | Cursor for loop checks only existence of data. |
Compliant Solution - ★★★★★
declare
l_employee_found boolean := false;
cursor c_employees is
select employee_id,last_name
from employees;
r_employee c_employees%rowtype;
begin
open c_employees;
fetch c_employees into r_employee;
l_employee_found := c_employees%found;
close c_employees;
if l_employee_found then
null; -- some processing;
end if;
end;
/References
- same as Trivadis G-4385