Actually only one (row) is read form the cursor, and then the function is left with a return. Because it's an unconditional return, the code within the loop will either execute once, or never. When no data is found NULL is returned. When an error occurs NULL is returned as well. So, why a loop?
Wouldn't it be better to have something like:
create or replace function XYZ(gid in number) return varchar2 is
l_c1 tab1.C1%TYPE; /* local variable to store C1 */
begin
select c1
into l_c1
from tab1
where id = gid;
return l_c1;
exception
when no_data_found
then return <some_error_code>; /* let the caller know that no data is found */
when others
then return 'ERROR: '||TO_CHAR(SQLCODE); /* return the error-code, preceded by the text ERROR for identification */
end;
Sure, a loop prevents an ORA-1422, but I don't think a loop construction should be abused for this. Just think about all loop controlling code that needs to be set up by the interpreter. tab1.ID should be unique, so a 1422 normally cannot occur. Robust programming however asks us to prevent any error. I would prefer to think about how a 1422 should be handled, and write some code accordingly.
Regards, Carel-Jan
===
If you think education is expensive, try ignorance. (Derek Bok)
===
At 09:39 28-12-03 -0800, you wrote:
Hi
if we assume it is implements this way (see below) there will only be one cursor since c_gid
is a bind variable and there for the cursor will be sharded from call to call of the function.
create or replace function XYZ (gid in number) return varchar2 is
cursor cur1(c_gid number) is select C1 from tab1 where id = c_gid;
begin
for x in cur1(gid) loop
return x.c1;
end loop;
return null;
exception
when others then return null;
end;
It will only be one coursor
Guang Mei wrote:
I have a function like below (psudo code). If cursor cur1 have multiple rows, would the code leave the cursor open when this function is called? So if this function is called 1000 times, I would have 1000 open cursors?function XYZ(gid in number) return varchar2 is cursor cur1 is select C1 from tab1 where ID = gid; begin for x in cur1 loop return x.c1; end loop; return null; exception when others then return null; end;
--
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