Sorry for my insistency but I would like to resume this discussion again.
A few days ago Gleb answered the question I asked before about 0 PK values
(look for "Re: auto_increment=0" topic in the archives).
I had a look at http://dev.mysql.com/doc/mysql/en/server-sql-mode.html and
found that using 0 is not recommended for PK values. But could you explain
As I mentioned before I used 0's for special purpose, e. g. for specifying
root user/category. What is the recommended way of doing this?
How do you specify, for instance, root category for products (if we want to
have _one and only_ root category)?
> -----Original Message-----
> From: Martijn Tonies [mailto:m.tonies@stripped]
> Sent: Thursday, February 10, 2005 2:31 PM
> To: Denis Gerasimov; Alec.Cawley@stripped; 'MySQL General List'
> Subject: Re: How to specify autoincrement primary key value
> > > > One simple question... AFAIK I can specify value for an
> > > > primary key (int) when inserting a record like this:
> > > >
> > > > INSERT INTO `tablename` (`id`, `name`) VALUES (1, 'test')
> > > >
> > > > But it doesn't work for id = 0. Why?
> > > >
> > > > I would like to use some primary key values for special purpose,
> > > 0
> > > > means root/default record and so on.
> > > > Is that recommended? Are there any alternative ways?
> > >
> > > Autoincrement starts from 1. That is the way it is, and cannot, I
> > > be changed.
> > Yes, it starts from 1, but concrete value CAN be changed to 0 manually.
> > Maybe it is better to ask: "Why can I set autoincrement primary key to 0
> > cannot do this using INSERT statement?"
> > >
> > > I would advise against using autoincrement keys for "special" uses.
> > > is muddling two different functions into one. Remeber that primary
> > > must be unique: if, at some time, you need to have more than one of a
> > > "special" value, you will be in trouble.
> > Sure, but the idea was to use 0 for root category or "root" access. It
> > to be reasonable at least.
> Then again... this is only an non-business-meaning ID value. If it's 0
> or 100 or 1293492342 -> it doesn't matter at all.
> > > The function of autoincrement
> > > keys is to assign unique record identifiers. Do not mix this with
> > > tasks.
> The meaning of auto-inc values is to make people lazy.
> With regards,
> Martijn Tonies
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