Re: Calling plSQL functions

Thanks for the code snippet Josh,

I'll give this method a try as it is only for a simple listing and will not
have to do too many things special.

Cheers
Lonnie

--- Josh Berkus <josh(at)agliodbs(dot)com> wrote:
> Lonnie, Tom:
>
> Here's a somewhat complicated example of what Tom's talking about from
> my own programs.
>
> HOWEVER, you should use this kind of structure sparingly, if at all.
> SQL is a declarative language, rather than a procedural one. For
> updates to groups of records, you should put the updates in sets and use
> declarative statements whenever possible, rather than a looping
> structure.
>
> If you find you *have* to do a lot of looping rather than taking a
> declarative approach, you might want to consider changing languages.
> PL/perl, PL/TCL and C are all much better equipped to handle loops and
> arrays than PL/pgSQL and SQL.
>
> The example, part of a 279-line function which calculates a weighted job
> score evaluation for an HR database:
>
> --Calculate DETAILS modifier
> --loop through details one at a time, adding to candidates
> --that have that detail
>
> count_odetails := count_details - COALESCE(count_rdetails, 0);
>
> IF count_odetails > 0 THEN
> insert_loop := 0;
> WHILE insert_loop < count_odetails LOOP
>
> SELECT detail_id INTO detail_no
> FROM order_details
> WHERE order_usq = v_order AND detail_req = FALSE
> ORDER BY detail_id
> LIMIT 1 OFFSET insert_loop;
>
> insert_loop := insert_loop + 1;
>
> UPDATE matches SET match_score = match_score +
> (20::NUMERIC/CAST(count_details AS
> NUMERIC))
> FROM candidate_details
> WHERE candidate_details.candidate_usq =
> matches.candidate_usq
> AND match_sq = match_id
> AND detail_id = detail_no;
>
> END LOOP;
> END IF;
>
> (NOTE: OFFSET will not accept any math if set dynamically {as above}.
> Thus, "LIMIT 1 OFFSET insert_loop + 1" will error).
>
> -Josh
>
> --
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