Re: Integrity Error

Actually, the line "invoice = models.ForeignKey(Invoice)" tells Django "An invoice item should always be attached to an invoince".

You must realize that models are what they claim to be... models. They are not items of their own, they just define how you would model a particular item in your database.

The problem in your test scenario is that the actual invoice items that you are creating are attached to no actual invoice : 

InvoiceItem.objects.create(sum=12, unit='Stunde', amount=100)
InvoiceItem.objects.create(sum=10, unit='Stunde', amount=120)

You would actually need to do it the other way around.

First, create the invoice,

my_test_invoice = Invoice.objects.create(created_at="2011-07-28", customer_id=1, payable_at='2012-12-12')

Then, create the items.

InvoiceItem.objects.create(sum=12, unit='Stunde', amount=100, invoice = my_test_invoice)
InvoiceItem.objects.create(sum=10, unit='Stunde', amount=120, invoice = my_test_invoice)

I actually don't use the create syntax, so you might need to call my_test_invoice's save method before creating the invoice items (In a foreign key relationship, you will always need to save the foreign key item before the item that has a foreign key to it, else it has no id and you get an integrity error).

Thomas

2011/8/26 Torsten <torstenzander@googlemail.com>

Thanks Thomas

your are right concerning the sum there is no need for that.
But you say:

Your invoice items have no invoice attribute, as the error says.

Isn't this line which defines the attribute ?
invoice = models.ForeignKey(Invoice)

Thanks
Torsten

On 26 Aug., 11:41, Thomas Orozco <g.orozco.tho...@gmail.com> wrote:
> Your invoice items have no invoice attribute, as the error says.
>
> By the way, although I'm not sure of what you're trying to achieve, let me
> point out that there is not really a need for a sum field in your invoice as
> you can just sum all the invoice items' amount (and respect the DRY
> principle - you use a few other similar issues).

> Le 26 août 2011 11:35, "Torsten" <torstenzan...@googlemail.com> a écrit :

>
>
>
>
>
>
>
> > Hi
>
> > I have the following model:
>
> > class Invoice(models.Model):
> > customer = models.ForeignKey(Customer)
> > project = models.ForeignKey(Project, blank=True, null=True)
> > sum = models.FloatField(default=0)
> > tax = models.IntegerField(default=16)
> > payed_at = models.DateField(blank=True, null=True)
> > payable_at = models.DateField('payable at')
> > created_at = models.DateTimeField(auto_now_add=True)
>
> > def invoice_number(self):
> > invoice_number = str(self.created_at.year) + '/' +
> > str(self.id)
> > return invoice_number
>
> > def __unicode__(self):
> > return unicode(str(self.created_at.year) + '/' + str(self.id))
>
> > class InvoiceItem(models.Model):
> > invoice = models.ForeignKey(Invoice)
> > text = models.TextField()
> > unit = models.CharField(max_length=255)
> > amount = models.IntegerField()
> > sum = models.FloatField()
>
> > and try to run this test
>
> > def test_save_invoice(self):
> > InvoiceItem.objects.create(sum=12, unit='Stunde', amount=100)
> > InvoiceItem.objects.create(sum=10, unit='Stunde', amount=120)
> > invoice = Invoice.objects.create(created_at="2011-07-28",
> > customer_id=1, payable_at='2012-12-12')
> > invoice.invoiceitem_set.all()
> > self.assertEqual(240, invoice.sum)
>
> > with this error:
> > IntegrityError: invoice_invoiceitem.invoice_id may not be NULL
>
> > since it is the relation id Django should take care for the
> > invoice_invoiceitem.invoice_id
>
> > Or is there anything wrong with the code ?
>
> > Torsten
>
> > --
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