class FieldSchema(models.Model):
_PROHIBITED_NAMES = ('__module__', '_schema', '_declared')
_MAX_LENGTH_DATA_TYPES = ('character', )
name = models.CharField(max_length=63)
model_schema = models.ForeignKey(ModelSchema,
on_delete=models.CASCADE,
related_name='fields')
data_type = models.CharField(max_length=16,
choices=FieldFactory.data_type_choices(),
editable=False)
null = models.BooleanField(default=False)
unique = models.BooleanField(default=False)
max_length = models.PositiveIntegerField(null=True)
class Meta:
unique_together = (('name', 'model_schema'), )
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
self._initial_name = self.name
self._initial_null = self.null
self._initial_field = self.get_registered_model_field()
self._schema_editor = FieldSchemaEditor(self._initial_field)
def save(self, **kwargs):
self.validate()
super().save(**kwargs)
self.update_last_modified()
model, field = self._get_model_with_field()
self._schema_editor.update_column(model, field)
def delete(self, **kwargs):
model, field = self._get_model_with_field()
self._schema_editor.drop_column(model, field)
self.update_last_modified()
super().delete(**kwargs)
def validate(self):
if self._initial_null and not self.null:
raise NullFieldChangedError(
f"Cannot change NULL field '{self.name}' to NOT NULL")
if self.name in self.get_prohibited_names():
raise InvalidFieldNameError(
f'{self.name} is not a valid field name')
def get_registered_model_field(self):
latest_model = self.model_schema.get_registered_model()
if latest_model and self.name:
try:
return latest_model._meta.get_field(self.name)
except FieldDoesNotExist:
pass
@classmethod
def get_prohibited_names(cls):
# TODO: return prohbited names based on backend
return cls._PROHIBITED_NAMES
@classmethod
def get_data_types(cls):
return FieldFactory.get_data_types()
@property
def db_column(self):
return slugify(self.name).replace('-', '_')
def requires_max_length(self):
return self.data_type in self.__class__._MAX_LENGTH_DATA_TYPES
def update_last_modified(self):
self.model_schema.last_modified = timezone.now()
def get_options(self):
"""
Get a dictionary of kwargs to be passed to the Django field constructor
"""
options = {'null': self.null, 'unique': self.unique}
if self.requires_max_length():
options[
'max_length'] = self.max_length or config.default_charfield_max_length(
)
return options
def _get_model_with_field(self):
model = self.model_schema.as_model()
try:
field = model._meta.get_field(self.db_column)
except FieldDoesNotExist:
field = None
return model, field
class FieldSchema(models.Model):
_PROHIBITED_NAMES = ("__module__", "_declared")
name = models.CharField(max_length=63)
model_schema = models.ForeignKey(ModelSchema, on_delete=models.CASCADE, related_name="fields")
class_name = models.TextField()
kwargs = FieldKwargsJSON(default=dict)
class Meta:
unique_together = (("name", "model_schema"),)
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
self._initial_name = self.name
self._initial_null = self.null
self._initial_field = self.get_registered_model_field()
self._schema_editor = FieldSchemaEditor(self._initial_field)
def save(self, **kwargs):
self.validate()
super().save(**kwargs)
self.update_last_modified()
model, field = self._get_model_with_field()
self._schema_editor.update_column(model, field)
def delete(self, **kwargs):
model, field = self._get_model_with_field()
self._schema_editor.drop_column(model, field)
self.update_last_modified()
super().delete(**kwargs)
def validate(self):
if self._initial_null and not self.null:
raise NullFieldChangedError(f"Cannot change NULL field '{self.name}' to NOT NULL")
if self.name in self.get_prohibited_names():
raise InvalidFieldNameError(f"{self.name} is not a valid field name")
def get_registered_model_field(self):
latest_model = self.model_schema.get_registered_model()
if latest_model and self.name:
try:
return latest_model._meta.get_field(self.name)
except FieldDoesNotExist:
pass
@classmethod
def get_prohibited_names(cls):
# TODO: return prohbited names based on backend
return cls._PROHIBITED_NAMES
@property
def db_column(self):
return slugify(self.name).replace("-", "_")
@property
def null(self):
return self.kwargs.get("null", False)
@null.setter
def null(self, value):
self.kwargs['null'] = value
def update_last_modified(self):
cache.update_last_modified(self.model_schema.initial_model_name)
def get_options(self):
return self.kwargs.copy()
def _get_model_with_field(self):
model = self.model_schema.as_model()
try:
field = model._meta.get_field(self.db_column)
except FieldDoesNotExist:
field = None
return model, field