On Fri, Feb 6, 2009 at 12:58 PM, Kevin Audleman <kevin.audle...@gmail.com>wrote:
>
> Thanks Alex!
>
> My Project class has the field
>
> client = models.ForeignKey(Client')
>
> Would I use this in my save() method to reference the parent Client?
> For instance
>
> class Project:
> def save():
> self.hourly_rate = client.hourly_rate
> ...
>
> Or is there some other way of working across the relationship?
>
> Cheers,
> Kevin
>
> On Feb 6, 9:46 am, Alex Gaynor <alex.gay...@gmail.com> wrote:
> > On Fri, Feb 6, 2009 at 12:43 PM, Kevin Audleman <
> kevin.audle...@gmail.com>wrote:
> >
> >
> >
> >
> >
> > > I'm building a simple time tracker. It has a table Clients and a table
> > > Projects and there is a one-to-many relationship between them. I have
> > > a field called hourly_rate that is in both tables. The reasoning is
> > > that in general the hourly rate is the same across projects based on
> > > the client, but if at some point the hourly_rate goes up, I need to
> > > keep track of the historical rate I charged on Projects. What I would
> > > like to do is, on creation of a new Project, automatically populate
> > > its hourly_rate field with the value from Clients. Is this possible to
> > > set up in django? I'm used to Filemaker where I have the ability to
> > > auto-populate fields on creation through relationships, but django is
> > > a new world unto me.
> >
> > > Thanks for your help,
> > > Kevin Audleman
> >
> > Yep this is possible, basically what you're going to want to do is
> override
> > the save() method on a Project so that when it gets created it just
> copies
> > it's Clients hourly pay, you can look for other examples of using this
> > technique to accomplish other things(such as automatically setting the
> > creation date on a field).
> >
> > Alex
> >
> > --
> > "I disapprove of what you say, but I will defend to the death your right
> to
> > say it." --Voltaire
> > "The people's good is the highest law."--Cicero
> >
>
It would look something like this:
class Project(models.Model):
def save(self, *args, **kwargs):
if not self.id:
self.hourly_rate = self.client.hourly_rate
super(Project, self).save(*args, **kwargs)
that way it only sets the hourly rate the first time you save a project, in
case you edit it later you don't want the hourly rate to change.
Alex
--
"I disapprove of what you say, but I will defend to the death your right to
say it." --Voltaire
"The people's good is the highest law."--Cicero
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