ormar/docs/api/fields/many-to-many.md

fields.many_to_many

forbid_through_relations

forbid_through_relations(through: Type["Model"]) -> None

Verifies if the through model does not have relations.

Arguments:

• through (Type['Model]): through Model to be checked

populate_m2m_params_based_on_to_model

populate_m2m_params_based_on_to_model(to: Type["Model"], nullable: bool) -> Tuple[Any, Any]

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

Arguments:

• to (Model class): target related ormar Model
• nullable (bool): marks field as optional/ required

Returns:

(tuple with target pydantic type and target col type): Tuple[List, Any]

ManyToMany

ManyToMany(to: "ToType", through: Optional["ToType"] = None, *, name: str = None, unique: bool = False, virtual: bool = False, **kwargs: Any, ,) -> "RelationProxy[T]"

Despite a name it's a function that returns constructed ManyToManyField. This function is actually used in model declaration (as ormar.ManyToMany(ToModel, through=ThroughModel)).

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

Arguments:

• to (Model class): target related ormar Model
• through (Model class): through model for m2m relation
• name (str): name of the database field - later called alias
• unique (bool): parameter passed to sqlalchemy.ForeignKey, unique flag
• virtual (bool): marks if relation is virtual. It is for reversed FK and auto generated FK on through model in Many2Many relations.
• kwargs (Any): all other args to be populated by BaseField

Returns:

(ManyToManyField): ormar ManyToManyField with m2m relation to selected model

ManyToManyField Objects

class ManyToManyField(ForeignKeyField,  ormar.QuerySetProtocol,  ormar.RelationProtocol)

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

get_source_related_name

 | get_source_related_name() -> 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 field name.

Returns:

(str): name of the related_name or default related name.

has_unresolved_forward_refs

 | has_unresolved_forward_refs() -> bool

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

Returns:

(bool): result of the check

evaluate_forward_ref

 | evaluate_forward_ref(globalns: Any, localns: Any) -> None

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

Arguments:

• globalns (Any): global namespace
• localns (Any): local namespace

Returns:

(None): None

get_relation_name

 | get_relation_name() -> str

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

Returns:

(bool): result of the check

get_source_model

 | get_source_model() -> Type["Model"]

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

Returns:

(Type["Model"]): source model

create_default_through_model

 | create_default_through_model() -> None

Creates default empty through model if no additional fields are required.