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from django.db import models
from django.core import exceptions
class DecimalCharField(models.DecimalField):
"""Like the standard django DecimalField but stored in a varchar
In order to gracefully read crappy data, use nullify_invalid=True.
This will set the field's value to None rather than raising an exception
whenever a non-null, non-decimal string is read from a queryset.
However, use this option with caution as it also prevents exceptions
from being raised during model property assignment. This could allow you
to "successfuly" save a ton of data when all that is really written
is NULL. It might be best to combine this with the null=False option.
"""
description = 'Decimal number stored as a varchar'
__metaclass__ = models.SubfieldBase
def __init__(self, verbose_name=None, name=None, max_digits=None,
decimal_places=None, nullify_invalid=False, **kwargs):
self.nullify_invalid = nullify_invalid
kwargs['max_length'] = max_digits + 1
super(DecimalCharField, self).__init__(verbose_name, name,
max_digits=max_digits, decimal_places=decimal_places, **kwargs)
def get_internal_type(self):
return "CharField"
def to_python(self, value):
try:
return super(DecimalCharField, self).to_python(value)
except exceptions.ValidationError:
if self.nullify_invalid:
return None
else:
raise
def get_db_prep_save(self, value, connection, prepared=False):
if prepared:
return value
else:
return self.get_prep_value(value)
def get_prep_value(self, value):
if value is None:
return value
return self.format_number(value)
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