From:
vinny <vinny@xxxxxxxxx>
Subject: Re:
R: Field's position in Table
To: "Sam Mason" <sam@xxxxxxxxxxxxx>
Cc: pgsql-general@xxxxxxxxxxxxxx
Date:
Monday, August 24, 2009, 2:38 PM
On Thu, 2009-08-20 at 12:16 +0100, Sam Mason
wrote: > On Thu, Aug 20, 2009 at 11:24:49AM +0200, vinny
wrote: > > I can't really think of any real reason to put the
field at a > > particular position, applications don't
reallty care about the order > > of fields. > >
Because it's very convenient for ad-hoc queries! PG currently
assumes > that the column order is the same as when it was
created but there are > (unimplemented) suggestions about how to
"fix" this. See for example: >
> http://archives.postgresql.org/pgsql-hackers/2006-12/msg00983.php>
> -- > Sam http://samason.me.uk/> But how is it
convenient exactly, is it just a timesaver so you can SELECT *
instead of having to type SELECT firstname, lastname,
email?
For me, saying all new fields must go at the end of the table is
like saying all new functions must go at the end of your C source
file. Not that it makes *any* difference to the end user, or other
applications using your libraries, but as developers we tend to
be more organized than the general public. Most programmers
habitually organize their source code to keep related functions
together. It seems sloppy to have 10 memory-related functions
together in the source, and then an 11th hidden 6 pages down in the
middle of file-related functions. And if you're writing OO code in
C++ or Java, you even group private variables and methods separately
from public ones. Most of the people who advocate tacking
new fields at the end of a table would never dream of following
this convention for source code.
So when I'm working in PgAdmin, I like to see my primary &
foreign keys listed first, then data fields in logical groupings, and
finally the standard "footer" fields we add to all tables like create
& update by/date. Whenever I'm developing and need
to reference a table definition, (or do a select * in pgAdmin for
sample data) I lose productivity having to scan through all the fields
repeatedly instead of seeing at a glance the fields I want because
I know where they *should* be in the listing. Sometimes I have to
scan through the fields several times before I finally see the one I
want, because it was in the middle of unrelated items. I
*never* code my applications to depend on field order; I'm referring to
development convenience only.
(Just my two cents, YMMV, etc)
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