Re: Calling Python functions with parameters

Jerry McRae wrote:
> I am having a problem with the simplest of Python functions, so I must be
> doing something wrong.  After hours of searching and trying many options, I
> need the key that my puny brain is missing here.
>
> I cannot pass parameters to a plpythonu function.  I have tried within psql
> and with pgAdmin III (which adds IN or INOUT to the parameter list - which I
> can't find documented).  I'm an advanced Python programmer but a beginning
> PostgreSQL user.
>
> Here is what I have, which I copied almost verbatim from example code:
> ----------------------------
> test_dev-# \p
> create or replace function testf5i(a integer,b integer)
>  RETURNS integer AS $$
>   if a > b:
>     return a
>   return b
> $$ language plpythonu
>
>
> test_dev-# \g
> CREATE FUNCTION
> test_dev=# select testf5i(1,2);
> ERROR:  plpython: function "testf5i" failed
> DETAIL:  exceptions.NameError: global name 'a' is not defined

That looks like the same error I received in my first attempts at
plpython. After muddling with it for some time (and this  was my first
practical Python code at all, so you can imagine how confused I was), I
added (the equivalent to your code) at the beginning:

a = a
b = b

As ridiculous as that looks, it's what worked for me. Although, function
contained a class with several methods (the function creates "slugs" on
the fly from proper names for use in URLs, eg. Élisabeth Carrière ->
elisabeth_carriere). So, maybe my own problems were related to that.
PlPython remains a mystery to me, in many respects. It's certainly *not*
the best way to learn Python.

> PS.  What I need to do, which I also could find not examples on the mailing
> lists or the Internet, is to de-normalize some tables (user, addresses,
> phones, emails) into one big view and then update the proper tables upon
> updates.  The web application then can just get one row and not have to deal
> with all the different tables
>
> ...
>
> (And I'm surprised that I could find no examples of anyone already doing
> this?  Is there something inherently wrong with this approach?)

Perhaps it's simply not worthwhile. That seems like a great deal of work
just to avoid having to deal with several tables. (I didn't end up using
my slug-creator function, myself, and moved that logic into the
application scripts.)

b