On 6/20/2012 11:46 AM, Melvyn Sopacua wrote:
On 20-6-2012 20:31, André Pang wrote:
Right. There's currently no way to enforce required=True at the database
level.
So, your model clearly defines that it doesn't allow empty values, yet
some were inserted? Can you pull this out of the abstract with an example?
There's no way for a model to disallow empty values, AFAIK. The example
I have resembles this:
class Foo(models.Model):
my_field = models.CharField(null=False, blank=True)
In Oracle's case, the null=False (which is the default) is ignored and
always coerced to null=True, which means that empty strings are allowed.
(I'm not sure what the behavior is for other databases; I guess it
depends on whether the backend regards NULL == '' or not.)
Since blank=True is an admin thing only, and required=True is an
attribute of a form and not a model, any non-form or non-admin code that
creates a model can insert an empty string into the database. Most of
the code we've written so far isn't form code nor admin code, e.g. we
have command-line Django scripts that import records from a legacy
FileMaker Pro database to Oracle, with a lot of garbage data containing
empty strings in various columns where they should be illegal.
Enforcing this at the database level would be nice.
I think a more worthwhile solution is to have the default value for a
field be propagated to the database as default value. In that case,
empty strings on NOT NULL columns will be consistent.
In our case, there is no sensible default value for the field; e.g. what
if the field's a ForeignKey or a primary key[1]? The schema we have
requires that the column have good data or not exist at all, which I
don't think is insensible.
1. In Oracle's case, what if you have a model with a primary key that's
a CharField? I suspect that Oracle backend will coerce that to be
null=True, so now you have a primary key field that could have NULL.
--
You received this message because you are subscribed to the Google Groups "Django
users" group.
To post to this group, send email to django-users@googlegroups.com.
To unsubscribe from this group, send email to
django-users+unsubscr...@googlegroups.com.
For more options, visit this group at
http://groups.google.com/group/django-users?hl=en.
