Hi all,
I wrote a custom field which should get an object by a primary key
value (chainId). The base storage type is an int. I have a call that
does "obj.save(force_update=True)", and I get this "may not be NULL"
error. I set a debug point in execute_sql(), and indeed, it seems to
say "UPDATE ... fieldname = NULL, ... WHERE ...". My get_db_prep_value
() looks like this:
def get_db_prep_value(self, value):
assert isinstance(value.chainId, (int, long))
return value.chainId
If anyone has encountered a similar problem, I'd appreciate it.
regards,
Nicholas
class ImmutableRefField(models.Field):
__metaclass__ = models.SubfieldBase
def __init__(self, typegetter, *argv, **kwargs):
self.typegetter = typegetter
models.Field.__init__(self, *argv, **kwargs)
def get_internal_type(self):
return "IntegerField"
def to_python(self, value):
if isinstance(value, (int, long, str)):
clstype = self.typegetter()
assert issubclass(clstype, ImmutableModel)
return clstype.ReferenceGetter(clstype, value)
elif isinstance(value, (ImmutableModel,
ImmutableModel.ReferenceGetter)):
return value
raise NotImplementedError, "unknown value type %r" %(value)
# dynamically typed is nice; this could be a reference or an
object
def get_db_prep_value(self, value):
assert isinstance(value.chainId, (int, long))
return value.chainId
def get_db_prep_lookup(self, lookup_type, value):
if lookup_type == 'exact':
return [self.get_db_prep_value(value)]
pyhelp = help; import pdb; pdb.set_trace()
if lookup_type == 'in':
return [force_unicode(v) for v in value]
if lookup_type == 'isnull':
return []
raise FieldError('Invalid lookup type: %r' % lookup_type)
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