Anthony, that's quite helpful advice.
I'd suspected that has something to do with different errors and
couldn't go as far as you showed in your post. Thanks.
On Jan 29, 7:33 pm, Anthony <abasta...@gmail.com> wrote:
> On Saturday, January 29, 2011 6:59:39 PM UTC-5, AW wrote:
> > The following two lines of code are often used in the web2py book:
>
> > 1. db.define_table('person', Field('name', unique=True))
> > 2. db.person.name.requires = IS_NOT_IN_DB(db, 'person.name')
>
> > Well, given that line 1 already avoids race condition at the database
> > level, isn't line 2 more or less redundant? Thanks in advance for your
> > opinion.
>
> If I understand correctly, line 2 allows validation at the form level (i.e.,
> before attempting to commit to the database), which enables more
> sophisticated handling of validation errors. For example, there is an error
> message (which can be customized) associated with failure of IS_NOT_IN_DB,
> which will be displayed to the user upon rejection of the form submittal. I
> don't think that would happen if you had only line 1 without line 2.
>
> Anthony
