How to use sql call a pl/sql function

Question

Hi there,
I have a pl/sql function package as below:
Create or Replace package test10 as
P_DESFORMAT VARCHAR2(10);
DESFORMAT VARCHAR2(10);
function m_tot_u1Formula(m_o_uns number,m_t_uns number,m_v_uns number)return NUMBER ;
     function m_tot_res1Formula(m_o_res number,m_t_res number)return NUMBER;
     function m_occ_u1Formula(m_o_uns number,m_t_uns number)return NUMBER ;
     function m_onrpun1Formula(m_o_uns in number,m_o_res in number)return NUMBER ;
     function m_tenpun1Formula(m_t_res in number,m_t_uns in number)return NUMBER ;
     function m_occpun1formula(m_occ_u in number, m_tot_res in number) return number ;
     function m_vac_rate1formula(m_v_uns in number,m_tot_u in number) return number;
     function m_onrpha1Formula(m_o_res in number,m_area in number) return NUMBER;
     function m_tenpha1Formula(m_t_res in number,m_area in number)return NUMBER ;
     function m_occpha1Formula(m_area in number,m_tot_res in number)return number;
     function P_DESFORMATValidTrigger return boolean;
END test10;
CREATE OR REPLACE PACKAGE BODY test10 AS
function m_tot_u1Formula(m_o_uns number,m_t_uns number,m_v_uns number)return NUMBER is
begin
RETURN m_o_uns + m_t_uns + m_v_uns;
end;
function m_tot_res1Formula(m_o_res number,m_t_res number)return NUMBER is
begin
RETURN m_o_res + m_t_res;
end;
function m_occ_u1Formula(m_o_uns number,m_t_uns number)return NUMBER is
begin
RETURN m_o_uns + m_t_uns;
end;
function m_onrpun1Formula(m_o_uns in number,m_o_res in number)return NUMBER is
begin
IF m_o_uns > 0 THEN
RETURN m_o_res / m_o_uns;
ELSE
     RETURN NULL;
END IF;
end;
function m_tenpun1Formula(m_t_res in number,m_t_uns in number)return NUMBER is
begin
IF m_t_uns > 0 THEN
RETURN m_t_res/m_t_uns;
ELSE
     RETURN NULL;
END IF;
end;
function m_occpun1formula(m_occ_u in number,m_tot_res in number) return number is
begin
IF m_occ_u > 0 THEN
RETURN m_tot_res / m_occ_u;
ELSE
     RETURN NULL;
END IF;
end;
function m_vac_rate1formula(m_v_uns in number,m_tot_u in number) return number is
begin
IF m_tot_u > 0 THEN
RETURN 100 * m_v_uns / m_tot_u;
ELSE
     RETURN NULL;
END IF;
end;
function m_onrpha1Formula(m_o_res in number,m_area in number) return NUMBER is
begin
IF m_o_res > 0 THEN
RETURN m_o_res / m_area;
ELSE
     RETURN NULL;
END IF;
end;
function m_tenpha1Formula(m_t_res in number,m_area in number)return NUMBER is
begin
IF m_t_res > 0 THEN
     RETURN m_t_res / m_area;
ELSE
     RETURN NULL;
END IF;
end;
function m_occpha1Formula(m_area in number,m_tot_res in number)return number is
begin
IF m_area > 0 THEN
RETURN m_tot_res / m_area;
ELSE
     RETURN NULL;
END IF;
end;
function P_DESFORMATValidTrigger return boolean is
begin
DESFORMAT := P_DESFORMAT;
return (TRUE);
end;
END test10 ;
the package is compiled successfully.
And my sql statement will call those function in this package such as:
select test10.m_tot_u1Formula(m_o_uns ,m_t_uns ,m_v_uns) m_tot_u,
test10.m_tot_res1Formula(m_o_res,m_t_res)m_tot_res,
test.m_occ_u1Formula(m_o_uns ,m_t_uns)m_occ_u,
test10.m_onrpun1Formula(m_o_uns ,m_o_res )m_onrpun,
test10.m_tenpun1Formula(m_t_res ,m_t_uns )m_tenpun,
test10.m_occpun1formula(:m_occ_u , :m_tot_res )m_occpun,
test10.m_vac_rate1formula(m_v_uns ,m_tot_u ) m_vac_rate,
test10.m_onrpha1Formula(m_o_res ,m_area ) m_onrpha,
test10.m_tenpha1Formula(m_t_res ,m_area ) m_tenpha,
test.m_occpha1Formula(m_area , :m_tot_res ) m_occpha
from ..... where.....
Is it right to call those functions? Thanks in advance.
Appcat

Answer 1

I spoke too soon on the impracticality of a function-based index on a view. My recollection was that the CBO wasn't smart enough to recognize that a FBI on an expression like (col1*col2) could be used to resolve queries that involved a simple transform (i.e. col2*col1), which tended to force you to have a user-defined function behind the FBI to make sure that someone cleaning up code didn't accidentally make the index unusable. Now that I've actually tested it, my recollection, at least on 10.2, is clearly incorrect.
There's certainly a matter of personal taste here. If I knew what these variables were intended to represent, I'd have no problem maintaining either syntax because it should be relatively obvious whether either piece of code is suspect. I do have to confess that I had to look up the syntax for the NULLIF function yesterday in order to reply to this thread-- my wager is that if I had to look it up, a good fraction of the PL/SQL programmers out there would have had to look it up as well and might not immediately recognize this as an inverted division by 0 test.
From a maintenance standpoint, I would personally rather have the package where I can zoom in on the particular function I'm interested in, rather than looking at a view that may be doing a dozen rather similar calculations. I'm a bit more confident that I (or some new maintenance programmer on my team) could change the logic in the function without inadvertently screwing up any of the other functions in the package than I would be that I (or they) would accidentally screw up the view. Clearly, robust test scripts and an automated test suite would help tremendously in either case, and neither change should be too difficult, but my experience is that the package is the easier construct to modify or add to. I certainly believe that other people/ organizations would have different experiences and other people might prefer the view approach. I certainly wouldn't oppose a view-based approach, just as I wouldn't oppose a package.
There's also still the matter of having a table with every valid input if a view is to be practical. It's certainly possible that such a table exists, but it seems equally possible that there are either many such tables, that these functions are doing calculations on values that aren't stored in tables, etc., in which case a package would be the better solution.
Justin