foreign_key

ForeignKeyConstraint dataclass

Internal container to store ForeignKey definitions used later to produce sqlalchemy.ForeignKeys

Source code in ormar\fields\foreign_key.py

@dataclass
class ForeignKeyConstraint:
    """
    Internal container to store ForeignKey definitions used later
    to produce sqlalchemy.ForeignKeys
    """

    reference: Union[str, sqlalchemy.Column]
    name: Optional[str]
    ondelete: Optional[str]
    onupdate: Optional[str]

ForeignKeyField

Bases: BaseField

Actual class returned from ForeignKey function call and stored in model_fields.

Source code in ormar\fields\foreign_key.py

class ForeignKeyField(BaseField):
    """
    Actual class returned from ForeignKey function call and stored in model_fields.
    """

    def __init__(self, **kwargs: Any) -> None:
        if TYPE_CHECKING:  # pragma: no cover
            self.__type__: type
            self.to: Type["Model"]
        self.ondelete: str = kwargs.pop("ondelete", None)
        self.onupdate: str = kwargs.pop("onupdate", None)
        super().__init__(**kwargs)

    def get_source_related_name(self) -> str:
        """
        Returns name to use for source relation name.
        For FK it's the same, differs for m2m fields.
        It's either set as `related_name` or by default it's owner model. get_name + 's'
        :return: name of the related_name or default related name.
        :rtype: str
        """
        return self.get_related_name()

    def get_related_name(self) -> str:
        """
        Returns name to use for reverse relation.
        It's either set as `related_name` or by default it's owner model. get_name + 's'
        :return: name of the related_name or default related name.
        :rtype: str
        """
        return self.related_name or self.owner.get_name() + "s"

    def default_target_field_name(self) -> str:
        """
        Returns default target model name on through model.
        :return: name of the field
        :rtype: str
        """
        prefix = "from_" if self.self_reference else ""
        return self.through_reverse_relation_name or f"{prefix}{self.to.get_name()}"

    def default_source_field_name(self) -> str:
        """
        Returns default target model name on through model.
        :return: name of the field
        :rtype: str
        """
        prefix = "to_" if self.self_reference else ""
        return self.through_relation_name or f"{prefix}{self.owner.get_name()}"

    def evaluate_forward_ref(self, globalns: Any, localns: Any) -> None:
        """
        Evaluates the ForwardRef to actual Field based on global and local namespaces

        :param globalns: global namespace
        :type globalns: Any
        :param localns: local namespace
        :type localns: Any
        :return: None
        :rtype: None
        """
        if self.to.__class__ == ForwardRef:
            self.to = evaluate_forwardref(
                self.to, globalns, localns or None  # type: ignore
            )
            (
                self.__type__,
                self.constraints,
                self.column_type,
            ) = populate_fk_params_based_on_to_model(
                to=self.to,
                nullable=self.nullable,
                ondelete=self.ondelete,
                onupdate=self.onupdate,
            )

    def _extract_model_from_sequence(
        self, value: List, child: "Model", to_register: bool
    ) -> List["Model"]:
        """
        Takes a list of Models and registers them on parent.
        Registration is mutual, so children have also reference to parent.

        Used in reverse FK relations.

        :param value: list of Model
        :type value: List
        :param child: child/ related Model
        :type child: Model
        :param to_register: flag if the relation should be set in RelationshipManager
        :type to_register: bool
        :return: list (if needed) registered Models
        :rtype: List["Model"]
        """
        return [
            self.expand_relationship(  # type: ignore
                value=val, child=child, to_register=to_register
            )
            for val in value
        ]

    def _register_existing_model(
        self, value: "Model", child: "Model", to_register: bool
    ) -> "Model":
        """
        Takes already created instance and registers it for parent.
        Registration is mutual, so children have also reference to parent.

        Used in reverse FK relations and normal FK for single models.

        :param value: already instantiated Model
        :type value: Model
        :param child: child/ related Model
        :type child: Model
        :param to_register: flag if the relation should be set in RelationshipManager
        :type to_register: bool
        :return: (if needed) registered Model
        :rtype: Model
        """
        if to_register:
            self.register_relation(model=value, child=child)
        return value

    def _construct_model_from_dict(
        self, value: dict, child: "Model", to_register: bool
    ) -> "Model":
        """
        Takes a dictionary, creates a instance and registers it for parent.
        If dictionary contains only one field and it's a pk it is a __pk_only__ model.
        Registration is mutual, so children have also reference to parent.

        Used in normal FK for dictionaries.

        :param value: dictionary of a Model
        :type value: dict
        :param child: child/ related Model
        :type child: Model
        :param to_register: flag if the relation should be set in RelationshipManager
        :type to_register: bool
        :return: (if needed) registered Model
        :rtype: Model
        """
        if len(value.keys()) == 1 and list(value.keys())[0] == self.to.Meta.pkname:
            value["__pk_only__"] = True
        model = self.to(**value)
        if to_register:
            self.register_relation(model=model, child=child)
        return model

    def _construct_model_from_pk(
        self, value: Any, child: "Model", to_register: bool
    ) -> "Model":
        """
        Takes a pk value, creates a dummy instance and registers it for parent.
        Registration is mutual, so children have also reference to parent.

        Used in normal FK for dictionaries.

        :param value: value of a related pk / fk column
        :type value: Any
        :param child: child/ related Model
        :type child: Model
        :param to_register: flag if the relation should be set in RelationshipManager
        :type to_register: bool
        :return: (if needed) registered Model
        :rtype: Model
        """
        if self.to.pk_type() == uuid.UUID and isinstance(value, str):  # pragma: nocover
            value = uuid.UUID(value)
        if not isinstance(value, self.to.pk_type()):
            raise RelationshipInstanceError(
                f"Relationship error - ForeignKey {self.to.__name__} "
                f"is of type {self.to.pk_type()} "
                f"while {type(value)} passed as a parameter."
            )
        model = create_dummy_instance(fk=self.to, pk=value)
        if to_register:
            self.register_relation(model=model, child=child)
        return model

    def register_relation(self, model: "Model", child: "Model") -> None:
        """
        Registers relation between parent and child in relation manager.
        Relation manager is kep on each model (different instance).

        Used in Metaclass and sometimes some relations are missing
        (i.e. cloned Models in fastapi might miss one).

        :param model: parent model (with relation definition)
        :type model: Model class
        :param child: child model
        :type child: Model class
        """
        model._orm.add(parent=model, child=child, field=self)

    def has_unresolved_forward_refs(self) -> bool:
        """
        Verifies if the filed has any ForwardRefs that require updating before the
        model can be used.

        :return: result of the check
        :rtype: bool
        """
        return self.to.__class__ == ForwardRef

    def expand_relationship(
        self,
        value: Any,
        child: Union["Model", "NewBaseModel"],
        to_register: bool = True,
    ) -> Optional[Union["Model", List["Model"]]]:
        """
        For relations the child model is first constructed (if needed),
        registered in relation and returned.
        For relation fields the value can be a pk value (Any type of field),
        dict (from Model) or actual instance/list of a "Model".

        Selects the appropriate constructor based on a passed value.

        :param value: a Model field value, returned untouched for non relation fields.
        :type value: Any
        :param child: a child Model to register
        :type child: Union["Model", "NewBaseModel"]
        :param to_register: flag if the relation should be set in RelationshipManager
        :type to_register: bool
        :return: returns a Model or a list of Models
        :rtype: Optional[Union["Model", List["Model"]]]
        """
        if value is None:
            return None if not self.virtual else []
        constructors = {
            f"{self.to.__name__}": self._register_existing_model,
            "dict": self._construct_model_from_dict,
            "list": self._extract_model_from_sequence,
        }

        model = constructors.get(  # type: ignore
            value.__class__.__name__, self._construct_model_from_pk
        )(value, child, to_register)
        return model

    def get_relation_name(self) -> str:  # pragma: no cover
        """
        Returns name of the relation, which can be a own name or through model
        names for m2m models

        :return: result of the check
        :rtype: bool
        """
        return self.name

    def get_source_model(self) -> Type["Model"]:  # pragma: no cover
        """
        Returns model from which the relation comes -> either owner or through model

        :return: source model
        :rtype: Type["Model"]
        """
        return self.owner

default_source_field_name()

Returns default target model name on through model.

Returns:

Type	Description
str	name of the field

Source code in ormar\fields\foreign_key.py

def default_source_field_name(self) -> str:
    """
    Returns default target model name on through model.
    :return: name of the field
    :rtype: str
    """
    prefix = "to_" if self.self_reference else ""
    return self.through_relation_name or f"{prefix}{self.owner.get_name()}"

default_target_field_name()

Returns default target model name on through model.

Returns:

Type	Description
str	name of the field

Source code in ormar\fields\foreign_key.py

def default_target_field_name(self) -> str:
    """
    Returns default target model name on through model.
    :return: name of the field
    :rtype: str
    """
    prefix = "from_" if self.self_reference else ""
    return self.through_reverse_relation_name or f"{prefix}{self.to.get_name()}"

evaluate_forward_ref(globalns, localns)

Evaluates the ForwardRef to actual Field based on global and local namespaces

Parameters:

Name	Type	Description	Default
globalns	Any	global namespace	required
localns	Any	local namespace	required

Returns:

Type	Description
None	None

Source code in ormar\fields\foreign_key.py

def evaluate_forward_ref(self, globalns: Any, localns: Any) -> None:
    """
    Evaluates the ForwardRef to actual Field based on global and local namespaces

    :param globalns: global namespace
    :type globalns: Any
    :param localns: local namespace
    :type localns: Any
    :return: None
    :rtype: None
    """
    if self.to.__class__ == ForwardRef:
        self.to = evaluate_forwardref(
            self.to, globalns, localns or None  # type: ignore
        )
        (
            self.__type__,
            self.constraints,
            self.column_type,
        ) = populate_fk_params_based_on_to_model(
            to=self.to,
            nullable=self.nullable,
            ondelete=self.ondelete,
            onupdate=self.onupdate,
        )

expand_relationship(value, child, to_register=True)

For relations the child model is first constructed (if needed), registered in relation and returned. For relation fields the value can be a pk value (Any type of field), dict (from Model) or actual instance/list of a "Model".

Selects the appropriate constructor based on a passed value.

Parameters:

Name	Type	Description	Default
value	Any	a Model field value, returned untouched for non relation fields.	required
child	Union[Model, NewBaseModel]	a child Model to register	required
to_register	bool	flag if the relation should be set in RelationshipManager	True

Returns:

Type	Description
Optional[Union["Model", List["Model"]]]	returns a Model or a list of Models

Source code in ormar\fields\foreign_key.py

def expand_relationship(
    self,
    value: Any,
    child: Union["Model", "NewBaseModel"],
    to_register: bool = True,
) -> Optional[Union["Model", List["Model"]]]:
    """
    For relations the child model is first constructed (if needed),
    registered in relation and returned.
    For relation fields the value can be a pk value (Any type of field),
    dict (from Model) or actual instance/list of a "Model".

    Selects the appropriate constructor based on a passed value.

    :param value: a Model field value, returned untouched for non relation fields.
    :type value: Any
    :param child: a child Model to register
    :type child: Union["Model", "NewBaseModel"]
    :param to_register: flag if the relation should be set in RelationshipManager
    :type to_register: bool
    :return: returns a Model or a list of Models
    :rtype: Optional[Union["Model", List["Model"]]]
    """
    if value is None:
        return None if not self.virtual else []
    constructors = {
        f"{self.to.__name__}": self._register_existing_model,
        "dict": self._construct_model_from_dict,
        "list": self._extract_model_from_sequence,
    }

    model = constructors.get(  # type: ignore
        value.__class__.__name__, self._construct_model_from_pk
    )(value, child, to_register)
    return model

get_related_name()

Returns name to use for reverse relation. It's either set as related_name or by default it's owner model. get_name + 's'

Returns:

Type	Description
str	name of the related_name or default related name.

Source code in ormar\fields\foreign_key.py

def get_related_name(self) -> str:
    """
    Returns name to use for reverse relation.
    It's either set as `related_name` or by default it's owner model. get_name + 's'
    :return: name of the related_name or default related name.
    :rtype: str
    """
    return self.related_name or self.owner.get_name() + "s"

get_relation_name()

Returns name of the relation, which can be a own name or through model names for m2m models

Returns:

Type	Description
bool	result of the check

Source code in ormar\fields\foreign_key.py

def get_relation_name(self) -> str:  # pragma: no cover
    """
    Returns name of the relation, which can be a own name or through model
    names for m2m models

    :return: result of the check
    :rtype: bool
    """
    return self.name

get_source_model()

Returns model from which the relation comes -> either owner or through model

Returns:

Type	Description
Type["Model"]	source model

Source code in ormar\fields\foreign_key.py

def get_source_model(self) -> Type["Model"]:  # pragma: no cover
    """
    Returns model from which the relation comes -> either owner or through model

    :return: source model
    :rtype: Type["Model"]
    """
    return self.owner

get_source_related_name()

Returns name to use for source relation name. For FK it's the same, differs for m2m fields. It's either set as related_name or by default it's owner model. get_name + 's'

Returns:

Type	Description
str	name of the related_name or default related name.

Source code in ormar\fields\foreign_key.py

def get_source_related_name(self) -> str:
    """
    Returns name to use for source relation name.
    For FK it's the same, differs for m2m fields.
    It's either set as `related_name` or by default it's owner model. get_name + 's'
    :return: name of the related_name or default related name.
    :rtype: str
    """
    return self.get_related_name()

has_unresolved_forward_refs()

Verifies if the filed has any ForwardRefs that require updating before the model can be used.

Returns:

Type	Description
bool	result of the check

Source code in ormar\fields\foreign_key.py

def has_unresolved_forward_refs(self) -> bool:
    """
    Verifies if the filed has any ForwardRefs that require updating before the
    model can be used.

    :return: result of the check
    :rtype: bool
    """
    return self.to.__class__ == ForwardRef

register_relation(model, child)

Registers relation between parent and child in relation manager. Relation manager is kep on each model (different instance).

Used in Metaclass and sometimes some relations are missing (i.e. cloned Models in fastapi might miss one).

Parameters:

Name	Type	Description	Default
model	Model	parent model (with relation definition)	required
child	Model	child model	required

Source code in ormar\fields\foreign_key.py

def register_relation(self, model: "Model", child: "Model") -> None:
    """
    Registers relation between parent and child in relation manager.
    Relation manager is kep on each model (different instance).

    Used in Metaclass and sometimes some relations are missing
    (i.e. cloned Models in fastapi might miss one).

    :param model: parent model (with relation definition)
    :type model: Model class
    :param child: child model
    :type child: Model class
    """
    model._orm.add(parent=model, child=child, field=self)

ForeignKey(to, *, name=None, unique=False, nullable=True, related_name=None, virtual=False, onupdate=None, ondelete=None, **kwargs)

Despite a name it's a function that returns constructed ForeignKeyField. This function is actually used in model declaration (as ormar.ForeignKey(ToModel)).

Accepts number of relation setting parameters as well as all BaseField ones.

Parameters:

Name	Type	Description	Default
to	Union[Type[T], ForwardRef]	target related ormar Model	required
name	str	name of the database field - later called alias	None
unique	bool	parameter passed to sqlalchemy.ForeignKey, unique flag	False
nullable	bool	marks field as optional/ required	True
related_name	str	name of reversed FK relation populated for you on to model	None
virtual	bool	marks if relation is virtual. It is for reversed FK and auto generated FK on through model in Many2Many relations.	False
onupdate	Union[ReferentialAction, str]	parameter passed to sqlalchemy.ForeignKey. How to treat child rows on update of parent (the one where FK is defined) model.	None
ondelete	Union[ReferentialAction, str]	parameter passed to sqlalchemy.ForeignKey. How to treat child rows on delete of parent (the one where FK is defined) model.	None
kwargs	Any	all other args to be populated by BaseField	{}

Returns:

Type	Description
ForeignKeyField	ormar ForeignKeyField with relation to selected model

Source code in ormar\fields\foreign_key.py

def ForeignKey(  # type: ignore # noqa CFQ002
    to: Union[Type["T"], "ForwardRef"],
    *,
    name: str = None,
    unique: bool = False,
    nullable: bool = True,
    related_name: str = None,
    virtual: bool = False,
    onupdate: Union[ReferentialAction, str] = None,
    ondelete: Union[ReferentialAction, str] = None,
    **kwargs: Any,
) -> "T":
    """
    Despite a name it's a function that returns constructed ForeignKeyField.
    This function is actually used in model declaration (as ormar.ForeignKey(ToModel)).

    Accepts number of relation setting parameters as well as all BaseField ones.

    :param to: target related ormar Model
    :type to: Model class
    :param name: name of the database field - later called alias
    :type name: str
    :param unique: parameter passed to sqlalchemy.ForeignKey, unique flag
    :type unique: bool
    :param nullable: marks field as optional/ required
    :type nullable: bool
    :param related_name: name of reversed FK relation populated for you on to model
    :type related_name: str
    :param virtual: marks if relation is virtual.
    It is for reversed FK and auto generated FK on through model in Many2Many relations.
    :type virtual: bool
    :param onupdate: parameter passed to sqlalchemy.ForeignKey.
    How to treat child rows on update of parent (the one where FK is defined) model.
    :type onupdate: Union[ReferentialAction, str]
    :param ondelete: parameter passed to sqlalchemy.ForeignKey.
    How to treat child rows on delete of parent (the one where FK is defined) model.
    :type ondelete: Union[ReferentialAction, str]
    :param kwargs: all other args to be populated by BaseField
    :type kwargs: Any
    :return: ormar ForeignKeyField with relation to selected model
    :rtype: ForeignKeyField
    """

    onupdate = validate_referential_action(action=onupdate)
    ondelete = validate_referential_action(action=ondelete)

    owner = kwargs.pop("owner", None)
    self_reference = kwargs.pop("self_reference", False)

    orders_by = kwargs.pop("orders_by", None)
    related_orders_by = kwargs.pop("related_orders_by", None)

    skip_reverse = kwargs.pop("skip_reverse", False)
    skip_field = kwargs.pop("skip_field", False)

    sql_nullable = kwargs.pop("sql_nullable", None)
    sql_nullable = nullable if sql_nullable is None else sql_nullable

    validate_not_allowed_fields(kwargs)

    if to.__class__ == ForwardRef:
        __type__ = to if not nullable else Optional[to]
        constraints: List = []
        column_type = None
    else:
        __type__, constraints, column_type = populate_fk_params_based_on_to_model(
            to=to,  # type: ignore
            nullable=nullable,
            ondelete=ondelete,
            onupdate=onupdate,
        )

    namespace = dict(
        __type__=__type__,
        to=to,
        through=None,
        alias=name,
        name=kwargs.pop("real_name", None),
        nullable=nullable,
        sql_nullable=sql_nullable,
        constraints=constraints,
        unique=unique,
        column_type=column_type,
        related_name=related_name,
        virtual=virtual,
        primary_key=False,
        index=False,
        pydantic_only=False,
        default=None,
        server_default=None,
        onupdate=onupdate,
        ondelete=ondelete,
        owner=owner,
        self_reference=self_reference,
        is_relation=True,
        orders_by=orders_by,
        related_orders_by=related_orders_by,
        skip_reverse=skip_reverse,
        skip_field=skip_field,
    )

    Field = type("ForeignKey", (ForeignKeyField, BaseField), {})
    return Field(**namespace)

create_dummy_instance(fk, pk=None)

Ormar never returns you a raw data. So if you have a related field that has a value populated it will construct you a Model instance out of it.

Creates a "fake" instance of passed Model from pk value. The instantiated Model has only pk value filled. To achieve this pk_only flag has to be passed as it skips the validation.

If the nested related Models are required they are set with -1 as pk value.

Parameters:

Name	Type	Description	Default
fk	Type[T]	class of the related Model to which instance should be constructed	required
pk	Any	value of the primary_key column	None

Returns:

Type	Description
Model	Model instance populated with only pk

Source code in ormar\fields\foreign_key.py

def create_dummy_instance(fk: Type["T"], pk: Any = None) -> "T":
    """
    Ormar never returns you a raw data.
    So if you have a related field that has a value populated
    it will construct you a Model instance out of it.

    Creates a "fake" instance of passed Model from pk value.
    The instantiated Model has only pk value filled.
    To achieve this __pk_only__ flag has to be passed as it skips the validation.

    If the nested related Models are required they are set with -1 as pk value.

    :param fk: class of the related Model to which instance should be constructed
    :type fk: Model class
    :param pk: value of the primary_key column
    :type pk: Any
    :return: Model instance populated with only pk
    :rtype: Model
    """
    init_dict = {
        **{fk.Meta.pkname: pk or -1, "__pk_only__": True},
        **{
            k: create_dummy_instance(v.to)
            for k, v in fk.Meta.model_fields.items()
            if v.is_relation and not v.nullable and not v.virtual
        },
    }
    return fk(**init_dict)

create_dummy_model(base_model, pk_field)

Used to construct a dummy pydantic model for type hints and pydantic validation. Populates only pk field and set it to desired type.

Parameters:

Name	Type	Description	Default
base_model	Type[T]	class of target dummy model	required
pk_field	Union[BaseField, ForeignKeyField, ManyToManyField]	ormar Field to be set on pydantic Model	required

Returns:

Type	Description
pydantic.BaseModel	constructed dummy model

Source code in ormar\fields\foreign_key.py

def create_dummy_model(
    base_model: Type["T"],
    pk_field: Union[BaseField, "ForeignKeyField", "ManyToManyField"],
) -> Type["BaseModel"]:
    """
    Used to construct a dummy pydantic model for type hints and pydantic validation.
    Populates only pk field and set it to desired type.

    :param base_model: class of target dummy model
    :type base_model: Model class
    :param pk_field: ormar Field to be set on pydantic Model
    :type pk_field: Union[BaseField, "ForeignKeyField", "ManyToManyField"]
    :return: constructed dummy model
    :rtype: pydantic.BaseModel
    """
    alias = (
        "".join(choices(string.ascii_uppercase, k=6))  # + uuid.uuid4().hex[:4]
    ).lower()
    fields = {f"{pk_field.name}": (pk_field.__type__, None)}

    dummy_model = create_model(  # type: ignore
        f"PkOnly{base_model.get_name(lower=False)}{alias}",
        __module__=base_model.__module__,
        **fields,  # type: ignore
    )
    return dummy_model

populate_fk_params_based_on_to_model(to, nullable, onupdate=None, ondelete=None)

Based on target to model to which relation leads to populates the type of the pydantic field to use, ForeignKey constraint and type of the target column field.

Parameters:

Name	Type	Description	Default
to	Type[T]	target related ormar Model	required
nullable	bool	marks field as optional/ required	required
onupdate	str	parameter passed to sqlalchemy.ForeignKey. How to treat child rows on update of parent (the one where FK is defined) model.	None
ondelete	str	parameter passed to sqlalchemy.ForeignKey. How to treat child rows on delete of parent (the one where FK is defined) model.	None

Returns:

Type	Description
Tuple[Any, List, Any]	tuple with target pydantic type, list of fk constraints and target col type

Source code in ormar\fields\foreign_key.py

def populate_fk_params_based_on_to_model(
    to: Type["T"], nullable: bool, onupdate: str = None, ondelete: str = None
) -> Tuple[Any, List, Any]:
    """
    Based on target to model to which relation leads to populates the type of the
    pydantic field to use, ForeignKey constraint and type of the target column field.

    :param to: target related ormar Model
    :type to: Model class
    :param nullable: marks field as optional/ required
    :type nullable: bool
    :param onupdate: parameter passed to sqlalchemy.ForeignKey.
    How to treat child rows on update of parent (the one where FK is defined) model.
    :type onupdate: str
    :param ondelete: parameter passed to sqlalchemy.ForeignKey.
    How to treat child rows on delete of parent (the one where FK is defined) model.
    :type ondelete: str
    :return: tuple with target pydantic type, list of fk constraints and target col type
    :rtype: Tuple[Any, List, Any]
    """
    fk_string = to.Meta.tablename + "." + to.get_column_alias(to.Meta.pkname)
    to_field = to.Meta.model_fields[to.Meta.pkname]
    pk_only_model = create_dummy_model(to, to_field)
    __type__ = (
        Union[to_field.__type__, to, pk_only_model]
        if not nullable
        else Optional[Union[to_field.__type__, to, pk_only_model]]
    )
    constraints = [
        ForeignKeyConstraint(
            reference=fk_string, ondelete=ondelete, onupdate=onupdate, name=None
        )
    ]
    column_type = to_field.column_type
    return __type__, constraints, column_type

validate_not_allowed_fields(kwargs)

Verifies if not allowed parameters are set on relation models. Usually they are omitted later anyway but this way it's explicitly notify the user that it's not allowed/ supported.

Parameters:

Name	Type	Description	Default
kwargs	Dict	dict of kwargs to verify passed to relation field	required

Raises:

Type	Description
ModelDefinitionError	if any forbidden field is set

Source code in ormar\fields\foreign_key.py

def validate_not_allowed_fields(kwargs: Dict) -> None:
    """
    Verifies if not allowed parameters are set on relation models.
    Usually they are omitted later anyway but this way it's explicitly
    notify the user that it's not allowed/ supported.

    :raises ModelDefinitionError: if any forbidden field is set
    :param kwargs: dict of kwargs to verify passed to relation field
    :type kwargs: Dict
    """
    default = kwargs.pop("default", None)
    encrypt_secret = kwargs.pop("encrypt_secret", None)
    encrypt_backend = kwargs.pop("encrypt_backend", None)
    encrypt_custom_backend = kwargs.pop("encrypt_custom_backend", None)
    overwrite_pydantic_type = kwargs.pop("overwrite_pydantic_type", None)

    not_supported = [
        default,
        encrypt_secret,
        encrypt_backend,
        encrypt_custom_backend,
        overwrite_pydantic_type,
    ]
    if any(x is not None for x in not_supported):
        raise ModelDefinitionError(
            f"Argument {next((x for x in not_supported if x is not None))} "
            f"is not supported "
            "on relation fields!"
        )

validate_referential_action(action)

Validation onupdate and ondelete action cast to a string value

Parameters:

Name	Type	Description	Default
action	Optional[Union[ReferentialAction, str]]	referential action attribute or name string	required

Raises:

Type	Description
ModelDefinitionError	if action is a not valid name string value

Source code in ormar\fields\foreign_key.py

def validate_referential_action(
    action: Optional[Union[ReferentialAction, str]],
) -> Optional[str]:
    """
    Validation `onupdate` and `ondelete` action cast to a string value

    :raises ModelDefinitionError: if action is a not valid name string value
    :param action: referential action attribute or name string
    :type action: Optional[Union[ReferentialAction, str]]
    :rtype: Optional[str]
    """

    if action is not None and not isinstance(action, ReferentialAction):
        try:
            action = ReferentialAction(action.upper())
        except (ValueError, AttributeError):
            raise ModelDefinitionError(f"{action} ReferentialAction not supported.")

    return action.value if action is not None else None