Hey Karen. I used manage.py validate. My model validated before I
added the abstract class and changed the class signatures. But I
probably did something silly. Here is a chunk of the code:
# will use this for subclassing into our item subtypes
class AbstractType(models.Model):
name = models.CharField(max_length=100)
class Meta:
abstract = True
class Item(models.Model):
"""Item information for survey pages - pages will contain one or
more of these"""
sub_item = models.ForeignKey(AbstractType)
order = models.IntegerField()
class Admin:
pass
class Page(models.Model):
"""Page information for pages - surveys will contain one or more
of these"""
survey = models.ForeignKey(Survey)
item = models.ForeignKey(Item)
order = models.IntegerField()
file_name = models.CharField(max_length=50)
class Admin:
pass
class RadioBoxType(AbstractType):
"""A Radio Button object with its specific attributes"""
question_text = models.CharField(max_length=100)
question_sub_text = models.CharField(max_length=100)
item_type = models.CharField(max_length=20)
required = models.BooleanField()
randomize = models.BooleanField()
splitlist = models.BooleanField()
include_other = models.BooleanField()
other_prompt = models.CharField(max_length=100)
other_maxlen = models.IntegerField()
other_box_size = models.IntegerField()
class Admin:
pass
Well there is some of the model code - thanks for taking a look - I
think I need to spend a couple of weeks reading 24 hours a day to get
up to speed on all this technology, But I have just escaped from dot
niet and asp and sql server etc etc. Oh, what a feeling, what a rush!
Cheers
On May 6, 2:34 pm, "Karen Tracey" <[EMAIL PROTECTED]> wrote:
> On Tue, May 6, 2008 at 2:25 PM, Peter Bailey <[EMAIL PROTECTED]> wrote:
>
> > Hey alen. I have tried implementing this and it makes good sense as
> > far as I can see, but when I validate the model I always get an
> > AttributeError: 'NoneType' object has no attribute 'name'.
>
> How are you validating the model?
>
> I have tried removing name from the definition of the class - same
>
> > message (not sure where it is getting 'name' from since I deleted it.
> > I also looked around and saw that some other have had similar
> > problems, and it seemed to be a string definition problem. So I put
> > back 'name' and changed it to an IntegerField - same unhappy result.
>
> > Do you have any notion of what the problem is? The code looks right to
> > me.
>
> It sounds like you have some code somewhere that is expecting to always be
> handed an instance of your model, and thus be able to access the field
> 'name', but it is in fact sometimes getting handed None. When handed None,
> it still tries to access 'name', but since None has no attribute 'name', you
> get the error. If you post the code someone could probably help pinpoint
> the error more specifically.
>
> Karen
>
>
>
> > Thanks,
>
> > Peter
>
> > On May 6, 1:33 pm, Peter Bailey <[EMAIL PROTECTED]> wrote:
> > > Thanks very much for your solution and reply alen. I'm learning the
> > > ins and outs of python and django at the same time - fun adventure -
> > > so far python is blowing me away - I love it. Better than anything I
> > > have used before - 3 assemblers,c, c++ java, vb, ruby, php, asp, etc
> > > (guess I am dating myself lol - most people don't seem to even ever
> > > have looked at assembler these days. I used to love it - 7 years of
> > > that after university) Oh, and of course C was always the bomb too :-)
>
> > > Thanks again,
>
> > > Peter
>
> > > On May 6, 12:46 pm, "[EMAIL PROTECTED]" <[EMAIL PROTECTED]>
> > > wrote:
>
> > > > Define a 'abstract' attribute of Meta inner class and set it to true
> > > > like so:
>
> > > > class AbstractType(models.Model):
> > > > name = models.CharField(max_length=100)
>
> > > > class Meta:
> > > > abstract = True
>
> > > > class RadioBoxTypes(AbstractType):
> > > > radio_lable = models.CharField(max_length=20)
>
> > > > Regards,
> > > > -Alen
>
> > > > On May 6, 5:43 pm, Peter Bailey <[EMAIL PROTECTED]> wrote:
>
> > > > > I have designed a small db model (on paper) and want to implement it
> > > > > in my models.py file. So far, this has been pretty straight forward,
> > > > > but I have a generic superclass and several subclasses, and I am
> > > > > unsure how to implement this.
>
> > > > > My DB has page objects (webpages) with a few common attributes, and
> > a
> > > > > fk to an Item object. The item object is the generic superclass. It
> > > > > could be a RadioType, a CheckBoxType, a VerbatimType, etc. These all
> > > > > have attributes specific to themselves.
>
> > > > > Anyway, I don't grok how to set up this type of relationship in my
> > > > > models.py file. Is there a standard way of doing this, or does
> > anyone
> > > > > have an suggestions or can point me to some relevant info?
>
> > > > > e.g. Pages - pointed to by fk in Items
> > > > > ----------
>
> > > > > Items - has key to one of the below
> > > > > --------
>
> > > > > RadioBoxTypes CheckboxTypes VerbatimTypes etc
> > > > > ----------------------- -----------------------
> > > > > --------------------- ----
>
> > > > > Thanks very much. Sorry if this is a dumb question - always fun
> > being
> > > > > a newbie :-(
>
> > > > > Peter
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