def clean_linked_reference_dataset(self):
cleaned = self.cleaned_data
field = self.instance
if cleaned.get('data_type') == ReferenceDatasetField.DATA_TYPE_FOREIGN_KEY:
# Ensure a reference dataset to link to was provided
if cleaned.get('linked_reference_dataset') is None:
raise ValidationError('Please select a reference data set to link to')
# Ensure a reference dataset field cannot link to it's own parent
if self.reference_dataset == cleaned['linked_reference_dataset']:
raise ValidationError(
'A reference dataset record cannot point to itself'
)
# Do not allow users to change a foreign key relationship if records exist
if (
field.id
and cleaned['linked_reference_dataset']
!= field.linked_reference_dataset
):
matching_records = self.reference_dataset.get_records().exclude(
**{field.column_name: None}
)
if matching_records.exists():
raise forms.ValidationError(
'Unable to change linked reference dataset when '
'relations exist in this dataset'
)
# If this reference dataset syncs with an external database we need
# to ensure any linked fields also sync with the same database
ext_db = self.reference_dataset.external_database
linked_ext_db = cleaned['linked_reference_dataset'].external_database
if ext_db is not None and ext_db != linked_ext_db:
raise forms.ValidationError(
'Linked reference dataset does not exist on external database {}'.format(
ext_db.memorable_name
)
)
# Ensure a linked to reference dataset doesn't link back to this dataset
if has_circular_link(
self.reference_dataset, cleaned['linked_reference_dataset']
):
raise ValidationError(
'Unable to link to a dataset that links to this dataset'
)
return cleaned['linked_reference_dataset']
def save(
self, force_insert=False, force_update=False, using=None, update_fields=None
):
"""
On ReferenceDatasetField save update the associated table.
:param force_insert:
:param force_update:
:param using:
:param update_fields:
:return:
"""
ref_dataset = self.reference_dataset
# Disallow circular linking of reference datasets
if self.data_type == self.DATA_TYPE_FOREIGN_KEY and has_circular_link(
self.reference_dataset, self.linked_reference_dataset
):
raise ValidationError(
'Unable to link reference datasets back to each other'
)
# If this is a newly created field add it to the db
if self.id is None:
self._add_column_to_db()
else:
# Otherwise update where necessary
if self._original_column_name != self.column_name:
self._update_db_column_name()
if self._original_data_type != self.data_type:
self._update_db_column_data_type()
# Increment reference dataset major version if this is not the first save
if (
ref_dataset.major_version > 1 or ref_dataset.minor_version > 0
) or ref_dataset.get_records().exists():
self.reference_dataset.increment_major_version()
super().save()