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through_field

ThroughField

Bases: ForeignKeyField

Field class used to access ManyToMany model through model.

Source code in ormar\fields\through_field.py 
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class ThroughField(ForeignKeyField):
    """
    Field class used to access ManyToMany model through model.
    """

Through(to, *, name=None, related_name=None, **kwargs)

Despite a name it's a function that returns constructed ThroughField. It's a special field populated only for m2m relations. Accepts number of relation setting parameters as well as all BaseField ones.

Parameters:

Name Type Description Default
to ToType

target related ormar Model

 required
name Optional[str]

name of the database field - later called alias

 None
related_name Optional[str]

name of reversed FK relation populated for you on to 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\through_field.py 
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def Through(  # noqa CFQ002
    to: "ToType",
    *,
    name: Optional[str] = None,
    related_name: Optional[str] = None,
    **kwargs: Any
) -> Any:
    """
    Despite a name it's a function that returns constructed ThroughField.
    It's a special field populated only for m2m relations.
    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 related_name: name of reversed FK relation populated for you on to model
    :type related_name: str
    It is for reversed FK and auto generated FK on through model in Many2Many relations.
    :param kwargs: all other args to be populated by BaseField
    :type kwargs: Any
    :return: ormar ForeignKeyField with relation to selected model
    :rtype: ForeignKeyField
    """
    nullable = kwargs.pop("nullable", False)
    owner = kwargs.pop("owner", None)
    namespace = dict(
        __type__=to,
        to=to,
        through=None,
        alias=name,
        name=kwargs.pop("real_name", None),
        related_name=related_name,
        virtual=True,
        owner=owner,
        nullable=nullable,
        unique=False,
        column_type=None,
        primary_key=False,
        index=False,
        default=None,
        server_default=None,
        is_relation=True,
        is_through=True,
    )

    Field = type("Through", (ThroughField, BaseField), {})
    return Field(**namespace)