From: Sean Chittenden <sean@...>
Date: 2002-05-24T14:55:48+09:00
Subject: Re: cannot require 'postgres' from cgi

> > Why aren't you using DBI?
> 
> just one more thing to learn - haven't had time.  plus i'd read some
> things about speed issues and hadn't had time to investigate.  what
> are you opinions of it?

Use DBI 0.0.14 or later and the speed problems should be nil.  I use
DBI for tons of operations and as of yesterday, pumped over 30M rows
through it w/o a hitch.  :~)  Need a quick example?

dbh = DBI.connect('dbi:postgres:dbname:hostname','user','pass')
sql = 'SELECT or, some, other, sql, here FROM my_table AS mt WHERE mt.val1 = ? mt.val2 = ?'
dbh.select_all(sql, val1, val2) do |row|
  # do stuff w/ your row (array coresponding to the columns)
end
dbh.disconnect

Don't forget you can also use transactions:

dbh.transaction do |t|
  # t is just a normal DBH object
  t.do('INSERT INTO foo (val1, val2) VALUES (?,?)', val1, val2)
end

and statement handles:

sql = 'INSERT INTO foo (val1, val2) VALUES (?,?)'
dbh.prepare(sql) do |sth|
  # t is just a normal DBH object
  sth.execute(val1, val2)
end

statement handles are nice and faster for repeat operations.  You can
also go sth = dbh.prepare(sql): it's just a style preference.

> turns out (this took me a LONG time to determine) that the
> postgres.so lib has dependancies on other libs which are not to be
> found in the LD_LIBRARY_PATH (empty) of the default cgi environment
> but that WERE found in my own LD_LIBRARY_PATH.
> 
> it's a little troublesome that 'require' is unable to throw for this
> sort of error...
> 
> anyhow, i'm unsure of where to go from here
> 
>   - install postgress libs in /usr/lib
>   - modify ENV of running cgi
>   - staticaly link the postgres lib
> 
>   ???
> 
> any opinions on this?

See if you can set LD_RUN_PATH and recompile your postgres libs, then
you won't have to worry about LD_LIBRARY_PATH in the future.
Something tells me you're on Solaris, yes?  If so, I'm sorry. :~) That
OS has all kinds of strange SO problems from my experience.  Not
impossible to overcome, just a PITA.

-- 
Sean Chittenden