Re: proposal: plpgsql - iteration over fields of rec or row variable

2010/11/9 David E. Wheeler <david(at)kineticode(dot)com>:
> On Nov 9, 2010, at 9:34 AM, Tom Lane wrote:
>
>> I think there's a fairly fundamental contradiction involved here.
>> One of the basic design attributes of plpgsql is that it's strongly
>> typed.  Sometimes that's a blessing, and sometimes it's not, but
>> it's a fact.  There really isn't a good way to deal with run-time
>> field selection while still maintaining strong typing.  I do not
>> believe that the answer to that problem is "so let's break strong
>> typing".  Rather, the answer is that if that's what you need, you
>> need to use a different tool.  There's a reason we support multiple
>> PLs.
>
> Yeah, I think that Pavel wants to get at the record values with their types in tact. Not sure how that'd work though, really. If you know the type of the record columns already, you can just get them. But I'm not sure how you could introspect the column names and their types, and then get those types out without casting, except perhaps via EXECUTE…

every variable in plpgsql has known type descriptor. So it's not a
problem. The problem is a access to fields in cycle - and then you
need a simple trick like polymorphic parameters.

Pavel

>
> Best,
>
> David
>
>