ormar/docs/api/models/mixins/excludable-mixin.md

models.mixins.excludable_mixin

ExcludableMixin Objects

class ExcludableMixin(RelationMixin)

Used to include/exclude given set of fields on models during load and dict() calls.

get_child

 | @staticmethod
 | get_child(items: Union[Set, Dict, None], key: str = None) -> Union[Set, Dict, None]

Used to get nested dictionaries keys if they exists otherwise returns passed items.

Arguments:

• items (Union[Set, Dict, None]): bag of items to include or exclude
• key (str): name of the child to extract

Returns:

(Union[Set, Dict, None]): child extracted from items if exists

_populate_pk_column

 | @staticmethod
 | _populate_pk_column(model: Union[Type["Model"], Type["ModelRow"]], columns: List[str], use_alias: bool = False) -> List[str]

Adds primary key column/alias (depends on use_alias flag) to list of column names that are selected.

Arguments:

• model (Type["Model"]): model on columns are selected
• columns (List[str]): list of columns names
• use_alias (bool): flag to set if aliases or field names should be used

Returns:

(List[str]): list of columns names with pk column in it

own_table_columns

 | @classmethod
 | own_table_columns(cls, model: Union[Type["Model"], Type["ModelRow"]], excludable: ExcludableItems, alias: str = "", use_alias: bool = False) -> List[str]

Returns list of aliases or field names for given model. Aliases/names switch is use_alias flag.

If provided only fields included in fields will be returned. If provided fields in exclude_fields will be excluded in return.

Primary key field is always added and cannot be excluded (will be added anyway).

Arguments:

• alias (str): relation prefix
• excludable (ExcludableItems): structure of fields to include and exclude
• model (Type["Model"]): model on columns are selected
• use_alias (bool): flag if aliases or field names should be used

Returns:

(List[str]): list of column field names or aliases

_update_excluded_with_related

 | @classmethod
 | _update_excluded_with_related(cls, exclude: Union[Set, Dict, None]) -> Set

Used during generation of the dict(). To avoid cyclical references and max recurrence limit nested models have to exclude related models that are not mandatory.

For a main model (not nested) only nullable related field names are added to exclusion, for nested models all related models are excluded.

Arguments:

• exclude (Union[Set, Dict, None]): set/dict with fields to exclude

Returns:

(Union[Set, Dict]): set or dict with excluded fields added.

get_names_to_exclude

 | @classmethod
 | get_names_to_exclude(cls, excludable: ExcludableItems, alias: str) -> Set

Returns a set of models field names that should be explicitly excluded during model initialization.

Those fields will be set to None to avoid ormar/pydantic setting default values on them. They should be returned as None in any case.

Used in parsing data from database rows that construct Models by initializing them with dicts constructed from those db rows.

Arguments:

• alias (str): alias of current relation
• excludable (ExcludableItems): structure of fields to include and exclude

Returns:

(Set): set of field names that should be excluded