querysetproxy

QuerysetProxy

Bases: Generic[T]

Exposes QuerySet methods on relations, but also handles creating and removing of through Models for m2m relations.

Source code in ormar\relations\querysetproxy.py

class QuerysetProxy(Generic[T]):
    """
    Exposes QuerySet methods on relations, but also handles creating and removing
    of through Models for m2m relations.
    """

    if TYPE_CHECKING:  # pragma no cover
        relation: "Relation"

    def __init__(
        self,
        relation: "Relation",
        to: Type["T"],
        type_: "RelationType",
        qryset: "QuerySet[T]" = None,
    ) -> None:
        self.relation: "Relation" = relation
        self._queryset: Optional["QuerySet[T]"] = qryset
        self.type_: "RelationType" = type_
        self._owner: Union[CallableProxyType, "Model"] = self.relation.manager.owner
        self.related_field_name = self._owner.Meta.model_fields[
            self.relation.field_name
        ].get_related_name()
        self.to: Type[T] = to
        self.related_field = to.Meta.model_fields[self.related_field_name]
        self.owner_pk_value = self._owner.pk
        self.through_model_name = (
            self.related_field.through.get_name()
            if self.type_ == ormar.RelationType.MULTIPLE
            else ""
        )

    @property
    def queryset(self) -> "QuerySet[T]":
        """
        Returns queryset if it's set, AttributeError otherwise.
        :return: QuerySet
        :rtype: QuerySet
        """
        if not self._queryset:
            raise AttributeError
        return self._queryset

    @queryset.setter
    def queryset(self, value: "QuerySet") -> None:
        """
        Set's the queryset. Initialized in RelationProxy.
        :param value: QuerySet
        :type value: QuerySet
        """
        self._queryset = value

    def _assign_child_to_parent(self, child: Optional["T"]) -> None:
        """
        Registers child in parents RelationManager.

        :param child: child to register on parent side.
        :type child: Model
        """
        if child:
            owner = self._owner
            rel_name = self.relation.field_name
            setattr(owner, rel_name, child)

    def _register_related(self, child: Union["T", Sequence[Optional["T"]]]) -> None:
        """
        Registers child/ children in parents RelationManager.

        :param child: child or list of children models to register.
        :type child: Union[Model,List[Model]]
        """
        if isinstance(child, list):
            for subchild in child:
                self._assign_child_to_parent(subchild)
        else:
            assert isinstance(child, ormar.Model)
            child = cast("T", child)
            self._assign_child_to_parent(child)

    def _clean_items_on_load(self) -> None:
        """
        Cleans the current list of the related models.
        """
        if isinstance(self.relation.related_models, MutableSequence):
            for item in self.relation.related_models[:]:
                self.relation.remove(item)

    async def create_through_instance(self, child: "T", **kwargs: Any) -> None:
        """
        Crete a through model instance in the database for m2m relations.

        :param kwargs: dict of additional keyword arguments for through instance
        :type kwargs: Any
        :param child: child model instance
        :type child: Model
        """
        model_cls = self.relation.through
        owner_column = self.related_field.default_target_field_name()  # type: ignore
        child_column = self.related_field.default_source_field_name()  # type: ignore
        rel_kwargs = {owner_column: self._owner.pk, child_column: child.pk}
        final_kwargs = {**rel_kwargs, **kwargs}
        if child.pk is None:
            raise ModelPersistenceError(
                f"You cannot save {child.get_name()} "
                f"model without primary key set! \n"
                f"Save the child model first."
            )
        await model_cls(**final_kwargs).save()

    async def update_through_instance(self, child: "T", **kwargs: Any) -> None:
        """
        Updates a through model instance in the database for m2m relations.

        :param kwargs: dict of additional keyword arguments for through instance
        :type kwargs: Any
        :param child: child model instance
        :type child: Model
        """
        model_cls = self.relation.through
        owner_column = self.related_field.default_target_field_name()  # type: ignore
        child_column = self.related_field.default_source_field_name()  # type: ignore
        rel_kwargs = {owner_column: self._owner.pk, child_column: child.pk}
        through_model = await model_cls.objects.get(**rel_kwargs)
        await through_model.update(**kwargs)

    async def upsert_through_instance(self, child: "T", **kwargs: Any) -> None:
        """
        Updates a through model instance in the database for m2m relations if
        it already exists, else creates one.

        :param kwargs: dict of additional keyword arguments for through instance
        :type kwargs: Any
        :param child: child model instance
        :type child: Model
        """
        try:
            await self.update_through_instance(child=child, **kwargs)
        except NoMatch:
            await self.create_through_instance(child=child, **kwargs)

    async def delete_through_instance(self, child: "T") -> None:
        """
        Removes through model instance from the database for m2m relations.

        :param child: child model instance
        :type child: Model
        """
        queryset = ormar.QuerySet(model_cls=self.relation.through)  # type: ignore
        owner_column = self.related_field.default_target_field_name()  # type: ignore
        child_column = self.related_field.default_source_field_name()  # type: ignore
        kwargs = {owner_column: self._owner, child_column: child}
        link_instance = await queryset.filter(**kwargs).get()  # type: ignore
        await link_instance.delete()

    async def exists(self) -> bool:
        """
        Returns a bool value to confirm if there are rows matching the given criteria
        (applied with `filter` and `exclude` if set).

        Actual call delegated to QuerySet.

        :return: result of the check
        :rtype: bool
        """
        return await self.queryset.exists()

    async def count(self, distinct: bool = True) -> int:
        """
        Returns number of rows matching the given criteria
        (applied with `filter` and `exclude` if set before).
        If `distinct` is `True` (the default), this will return
        the number of primary rows selected. If `False`,
        the count will be the total number of rows returned
        (including extra rows for `one-to-many` or `many-to-many`
        left `select_related` table joins).
        `False` is the legacy (buggy) behavior for workflows that depend on it.

        Actual call delegated to QuerySet.

        :param distinct: flag if the primary table rows should be distinct or not
        :return: number of rows
        :rtype: int
        """
        return await self.queryset.count(distinct=distinct)

    async def max(self, columns: Union[str, List[str]]) -> Any:  # noqa: A003
        """
        Returns max value of columns for rows matching the given criteria
        (applied with `filter` and `exclude` if set before).

        :return: max value of column(s)
        :rtype: Any
        """
        return await self.queryset.max(columns=columns)

    async def min(self, columns: Union[str, List[str]]) -> Any:  # noqa: A003
        """
        Returns min value of columns for rows matching the given criteria
        (applied with `filter` and `exclude` if set before).

        :return: min value of column(s)
        :rtype: Any
        """
        return await self.queryset.min(columns=columns)

    async def sum(self, columns: Union[str, List[str]]) -> Any:  # noqa: A003
        """
        Returns sum value of columns for rows matching the given criteria
        (applied with `filter` and `exclude` if set before).

        :return: sum value of columns
        :rtype: int
        """
        return await self.queryset.sum(columns=columns)

    async def avg(self, columns: Union[str, List[str]]) -> Any:
        """
        Returns avg value of columns for rows matching the given criteria
        (applied with `filter` and `exclude` if set before).

        :return: avg value of columns
        :rtype: Union[int, float, List]
        """
        return await self.queryset.avg(columns=columns)

    async def clear(self, keep_reversed: bool = True) -> int:
        """
        Removes all related models from given relation.

        Removes all through models for m2m relation.

        For reverse FK relations keep_reversed flag marks if the reversed models
        should be kept or deleted from the database too (False means that models
        will be deleted, and not only removed from relation).

        :param keep_reversed: flag if reverse models in reverse FK should be deleted
        or not, keep_reversed=False deletes them from database.
        :type keep_reversed: bool
        :return: number of deleted models
        :rtype: int
        """
        if self.type_ == ormar.RelationType.MULTIPLE:
            queryset = ormar.QuerySet(model_cls=self.relation.through)  # type: ignore
            owner_column = self._owner.get_name()
        else:
            queryset = ormar.QuerySet(model_cls=self.relation.to)  # type: ignore
            owner_column = self.related_field_name
        kwargs = {owner_column: self._owner}
        self._clean_items_on_load()
        if keep_reversed and self.type_ == ormar.RelationType.REVERSE:
            update_kwrgs = {f"{owner_column}": None}
            return await queryset.filter(_exclude=False, **kwargs).update(
                each=False, **update_kwrgs
            )
        return await queryset.delete(**kwargs)  # type: ignore

    async def values(
        self, fields: Union[List, str, Set, Dict] = None, exclude_through: bool = False
    ) -> List:
        """
        Return a list of dictionaries with column values in order of the fields
        passed or all fields from queried models.

        To filter for given row use filter/exclude methods before values,
        to limit number of rows use limit/offset or paginate before values.

        Note that it always return a list even for one row from database.

        :param exclude_through: flag if through models should be excluded
        :type exclude_through: bool
        :param fields: field name or list of field names to extract from db
        :type fields:  Union[List, str, Set, Dict]
        """
        return await self.queryset.values(
            fields=fields, exclude_through=exclude_through
        )

    async def values_list(
        self,
        fields: Union[List, str, Set, Dict] = None,
        flatten: bool = False,
        exclude_through: bool = False,
    ) -> List:
        """
        Return a list of tuples with column values in order of the fields passed or
        all fields from queried models.

        When one field is passed you can flatten the list of tuples into list of values
        of that single field.

        To filter for given row use filter/exclude methods before values,
        to limit number of rows use limit/offset or paginate before values.

        Note that it always return a list even for one row from database.

        :param exclude_through: flag if through models should be excluded
        :type exclude_through: bool
        :param fields: field name or list of field names to extract from db
        :type fields: Union[str, List[str]]
        :param flatten: when one field is passed you can flatten the list of tuples
        :type flatten: bool
        """
        return await self.queryset.values(
            fields=fields,
            exclude_through=exclude_through,
            _as_dict=False,
            _flatten=flatten,
        )

    async def first(self, *args: Any, **kwargs: Any) -> "T":
        """
        Gets the first row from the db ordered by primary key column ascending.

        Actual call delegated to QuerySet.

        Passing args and/or kwargs is a shortcut and equals to calling
        `filter(*args, **kwargs).first()`.

        List of related models is cleared before the call.

        :param kwargs:
        :type kwargs:
        :return:
        :rtype: _asyncio.Future
        """
        first = await self.queryset.first(*args, **kwargs)
        self._clean_items_on_load()
        self._register_related(first)
        return first

    async def get_or_none(self, *args: Any, **kwargs: Any) -> Optional["T"]:
        """
        Gets the first row from the db meeting the criteria set by kwargs.

        If no criteria set it will return the last row in db sorted by pk.

        Passing args and/or kwargs is a shortcut and equals to calling
        `filter(*args, **kwargs).get_or_none()`.

        If not match is found None will be returned.

        :param kwargs: fields names and proper value types
        :type kwargs: Any
        :return: returned model
        :rtype: Model
        """
        try:
            get = await self.queryset.get(*args, **kwargs)
        except ormar.NoMatch:
            return None

        self._clean_items_on_load()
        self._register_related(get)
        return get

    async def get(self, *args: Any, **kwargs: Any) -> "T":
        """
        Gets the first row from the db meeting the criteria set by kwargs.

        If no criteria set it will return the last row in db sorted by pk.

        Passing args and/or kwargs is a shortcut and equals to calling
        `filter(*args, **kwargs).get()`.

        Actual call delegated to QuerySet.

        List of related models is cleared before the call.

        :raises NoMatch: if no rows are returned
        :raises MultipleMatches: if more than 1 row is returned.
        :param kwargs: fields names and proper value types
        :type kwargs: Any
        :return: returned model
        :rtype: Model
        """
        get = await self.queryset.get(*args, **kwargs)
        self._clean_items_on_load()
        self._register_related(get)
        return get

    async def all(self, *args: Any, **kwargs: Any) -> List["T"]:  # noqa: A003
        """
        Returns all rows from a database for given model for set filter options.

        Passing args and/or kwargs is a shortcut and equals to calling
        `filter(*args, **kwargs).all()`.

        If there are no rows meeting the criteria an empty list is returned.

        Actual call delegated to QuerySet.

        List of related models is cleared before the call.

        :param kwargs: fields names and proper value types
        :type kwargs: Any
        :return: list of returned models
        :rtype: List[Model]
        """
        all_items = await self.queryset.all(*args, **kwargs)
        self._clean_items_on_load()
        self._register_related(all_items)
        return all_items

    async def iterate(  # noqa: A003
        self,
        *args: Any,
        **kwargs: Any,
    ) -> AsyncGenerator["T", None]:
        """
        Return async iterable generator for all rows from a database for given model.

        Passing args and/or kwargs is a shortcut and equals to calling
        `filter(*args, **kwargs).iterate()`.

        If there are no rows meeting the criteria an empty async generator is returned.

        :param kwargs: fields names and proper value types
        :type kwargs: Any
        :return: asynchronous iterable generator of returned models
        :rtype: AsyncGenerator[Model]
        """

        async for item in self.queryset.iterate(*args, **kwargs):
            yield item

    async def create(self, **kwargs: Any) -> "T":
        """
        Creates the model instance, saves it in a database and returns the updates model
        (with pk populated if not passed and autoincrement is set).

        The allowed kwargs are `Model` fields names and proper value types.

        For m2m relation the through model is created automatically.

        Actual call delegated to QuerySet.

        :param kwargs: fields names and proper value types
        :type kwargs: Any
        :return: created model
        :rtype: Model
        """
        through_kwargs = kwargs.pop(self.through_model_name, {})
        if self.type_ == ormar.RelationType.REVERSE:
            kwargs[self.related_field_name] = self._owner
        created = await self.queryset.create(**kwargs)
        self._register_related(created)
        if self.type_ == ormar.RelationType.MULTIPLE:
            await self.create_through_instance(created, **through_kwargs)
        return created

    async def update(self, each: bool = False, **kwargs: Any) -> int:
        """
        Updates the model table after applying the filters from kwargs.

        You have to either pass a filter to narrow down a query or explicitly pass
        each=True flag to affect whole table.

        :param each: flag if whole table should be affected if no filter is passed
        :type each: bool
        :param kwargs: fields names and proper value types
        :type kwargs: Any
        :return: number of updated rows
        :rtype: int
        """
        # queryset proxy always have one filter for pk of parent model
        if (
            not each
            and (len(self.queryset.filter_clauses) + len(self.queryset.exclude_clauses))
            == 1
        ):
            raise QueryDefinitionError(
                "You cannot update without filtering the queryset first. "
                "If you want to update all rows use update(each=True, **kwargs)"
            )

        through_kwargs = kwargs.pop(self.through_model_name, {})
        children = await self.queryset.all()
        for child in children:
            await child.update(**kwargs)  # type: ignore
            if self.type_ == ormar.RelationType.MULTIPLE and through_kwargs:
                await self.update_through_instance(
                    child=child, **through_kwargs  # type: ignore
                )
        return len(children)

    async def get_or_create(
        self,
        _defaults: Optional[Dict[str, Any]] = None,
        *args: Any,
        **kwargs: Any,
    ) -> Tuple["T", bool]:
        """
        Combination of create and get methods.

        Tries to get a row meeting the criteria for kwargs
        and if `NoMatch` exception is raised
        it creates a new one with given kwargs and _defaults.

        :param kwargs: fields names and proper value types
        :type kwargs: Any
        :param _defaults: default values for creating object
        :type _defaults: Optional[Dict[str, Any]]
        :return: model instance and a boolean
        :rtype: Tuple("T", bool)
        """
        try:
            return await self.get(*args, **kwargs), False
        except NoMatch:
            _defaults = _defaults or {}
            return await self.create(**{**kwargs, **_defaults}), True

    async def update_or_create(self, **kwargs: Any) -> "T":
        """
        Updates the model, or in case there is no match in database creates a new one.

        Actual call delegated to QuerySet.

        :param kwargs: fields names and proper value types
        :type kwargs: Any
        :return: updated or created model
        :rtype: Model
        """
        pk_name = self.queryset.model_meta.pkname
        if "pk" in kwargs:
            kwargs[pk_name] = kwargs.pop("pk")
        if pk_name not in kwargs or kwargs.get(pk_name) is None:
            return await self.create(**kwargs)
        model = await self.queryset.get(pk=kwargs[pk_name])
        return await model.update(**kwargs)

    def filter(  # noqa: A003, A001
        self, *args: Any, **kwargs: Any
    ) -> "QuerysetProxy[T]":
        """
        Allows you to filter by any `Model` attribute/field
        as well as to fetch instances, with a filter across an FK relationship.

        You can use special filter suffix to change the filter operands:

        *  exact - like `album__name__exact='Malibu'` (exact match)
        *  iexact - like `album__name__iexact='malibu'` (exact match case insensitive)
        *  contains - like `album__name__contains='Mal'` (sql like)
        *  icontains - like `album__name__icontains='mal'` (sql like case insensitive)
        *  in - like `album__name__in=['Malibu', 'Barclay']` (sql in)
        *  isnull - like `album__name__isnull=True` (sql is null)
           (isnotnull `album__name__isnull=False` (sql is not null))
        *  gt - like `position__gt=3` (sql >)
        *  gte - like `position__gte=3` (sql >=)
        *  lt - like `position__lt=3` (sql <)
        *  lte - like `position__lte=3` (sql <=)
        *  startswith - like `album__name__startswith='Mal'` (exact start match)
        *  istartswith - like `album__name__istartswith='mal'` (case insensitive)
        *  endswith - like `album__name__endswith='ibu'` (exact end match)
        *  iendswith - like `album__name__iendswith='IBU'` (case insensitive)

        Actual call delegated to QuerySet.

        :param kwargs: fields names and proper value types
        :type kwargs: Any
        :return: filtered QuerysetProxy
        :rtype: QuerysetProxy
        """
        queryset = self.queryset.filter(*args, **kwargs)
        return self.__class__(
            relation=self.relation, type_=self.type_, to=self.to, qryset=queryset
        )

    def exclude(
        self, *args: Any, **kwargs: Any
    ) -> "QuerysetProxy[T]":  # noqa: A003, A001
        """
        Works exactly the same as filter and all modifiers (suffixes) are the same,
        but returns a *not* condition.

        So if you use `filter(name='John')` which is `where name = 'John'` in SQL,
        the `exclude(name='John')` equals to `where name <> 'John'`

        Note that all conditions are joined so if you pass multiple values it
        becomes a union of conditions.

        `exclude(name='John', age>=35)` will become
        `where not (name='John' and age>=35)`

        Actual call delegated to QuerySet.

        :param kwargs: fields names and proper value types
        :type kwargs: Any
        :return: filtered QuerysetProxy
        :rtype: QuerysetProxy
        """
        queryset = self.queryset.exclude(*args, **kwargs)
        return self.__class__(
            relation=self.relation, type_=self.type_, to=self.to, qryset=queryset
        )

    def select_all(self, follow: bool = False) -> "QuerysetProxy[T]":
        """
        By default adds only directly related models.

        If follow=True is set it adds also related models of related models.

        To not get stuck in an infinite loop as related models also keep a relation
        to parent model visited models set is kept.

        That way already visited models that are nested are loaded, but the load do not
        follow them inside. So Model A -> Model B -> Model C -> Model A -> Model X
        will load second Model A but will never follow into Model X.
        Nested relations of those kind need to be loaded manually.

        :param follow: flag to trigger deep save -
        by default only directly related models are saved
        with follow=True also related models of related models are saved
        :type follow: bool
        :return: reloaded Model
        :rtype: Model
        """
        queryset = self.queryset.select_all(follow=follow)
        return self.__class__(
            relation=self.relation, type_=self.type_, to=self.to, qryset=queryset
        )

    def select_related(self, related: Union[List, str]) -> "QuerysetProxy[T]":
        """
        Allows to prefetch related models during the same query.

        **With `select_related` always only one query is run against the database**,
        meaning that one (sometimes complicated) join is generated and later nested
        models are processed in python.

        To fetch related model use `ForeignKey` names.

        To chain related `Models` relation use double underscores between names.

        Actual call delegated to QuerySet.

        :param related: list of relation field names, can be linked by '__' to nest
        :type related: Union[List, str]
        :return: QuerysetProxy
        :rtype: QuerysetProxy
        """
        queryset = self.queryset.select_related(related)
        return self.__class__(
            relation=self.relation, type_=self.type_, to=self.to, qryset=queryset
        )

    def prefetch_related(self, related: Union[List, str]) -> "QuerysetProxy[T]":
        """
        Allows to prefetch related models during query - but opposite to
        `select_related` each subsequent model is fetched in a separate database query.

        **With `prefetch_related` always one query per Model is run against the
        database**, meaning that you will have multiple queries executed one
        after another.

        To fetch related model use `ForeignKey` names.

        To chain related `Models` relation use double underscores between names.

        Actual call delegated to QuerySet.

        :param related: list of relation field names, can be linked by '__' to nest
        :type related: Union[List, str]
        :return: QuerysetProxy
        :rtype: QuerysetProxy
        """
        queryset = self.queryset.prefetch_related(related)
        return self.__class__(
            relation=self.relation, type_=self.type_, to=self.to, qryset=queryset
        )

    def paginate(self, page: int, page_size: int = 20) -> "QuerysetProxy[T]":
        """
        You can paginate the result which is a combination of offset and limit clauses.
        Limit is set to page size and offset is set to (page-1) * page_size.

        Actual call delegated to QuerySet.

        :param page_size: numbers of items per page
        :type page_size: int
        :param page: page number
        :type page: int
        :return: QuerySet
        :rtype: QuerySet
        """
        queryset = self.queryset.paginate(page=page, page_size=page_size)
        return self.__class__(
            relation=self.relation, type_=self.type_, to=self.to, qryset=queryset
        )

    def limit(self, limit_count: int) -> "QuerysetProxy[T]":
        """
        You can limit the results to desired number of parent models.

        Actual call delegated to QuerySet.

        :param limit_count: number of models to limit
        :type limit_count: int
        :return: QuerysetProxy
        :rtype: QuerysetProxy
        """
        queryset = self.queryset.limit(limit_count)
        return self.__class__(
            relation=self.relation, type_=self.type_, to=self.to, qryset=queryset
        )

    def offset(self, offset: int) -> "QuerysetProxy[T]":
        """
        You can also offset the results by desired number of main models.

        Actual call delegated to QuerySet.

        :param offset: numbers of models to offset
        :type offset: int
        :return: QuerysetProxy
        :rtype: QuerysetProxy
        """
        queryset = self.queryset.offset(offset)
        return self.__class__(
            relation=self.relation, type_=self.type_, to=self.to, qryset=queryset
        )

    def fields(self, columns: Union[List, str, Set, Dict]) -> "QuerysetProxy[T]":
        """
        With `fields()` you can select subset of model columns to limit the data load.

        Note that `fields()` and `exclude_fields()` works both for main models
        (on normal queries like `get`, `all` etc.)
        as well as `select_related` and `prefetch_related`
        models (with nested notation).

        You can select specified fields by passing a `str, List[str], Set[str] or
        dict` with nested definition.

        To include related models use notation
        `{related_name}__{column}[__{optional_next} etc.]`.

        `fields()` can be called several times, building up the columns to select.

        If you include related models into `select_related()` call but you won't specify
        columns for those models in fields - implies a list of all fields for
        those nested models.

        Mandatory fields cannot be excluded as it will raise `ValidationError`,
         to exclude a field it has to be nullable.

        Pk column cannot be excluded - it's always auto added even if
        not explicitly included.

        You can also pass fields to include as dictionary or set.

        To mark a field as included in a dictionary use it's name as key
        and ellipsis as value.

        To traverse nested models use nested dictionaries.

        To include fields at last level instead of nested dictionary a set can be used.

        To include whole nested model specify model related field name and ellipsis.

        Actual call delegated to QuerySet.

        :param columns: columns to include
        :type columns: Union[List, str, Set, Dict]
        :return: QuerysetProxy
        :rtype: QuerysetProxy
        """
        queryset = self.queryset.fields(columns)
        return self.__class__(
            relation=self.relation, type_=self.type_, to=self.to, qryset=queryset
        )

    def exclude_fields(
        self, columns: Union[List, str, Set, Dict]
    ) -> "QuerysetProxy[T]":
        """
        With `exclude_fields()` you can select subset of model columns that will
        be excluded to limit the data load.

        It's the opposite of `fields()` method so check documentation above
        to see what options are available.

        Especially check above how you can pass also nested dictionaries
        and sets as a mask to exclude fields from whole hierarchy.

        Note that `fields()` and `exclude_fields()` works both for main models
        (on normal queries like `get`, `all` etc.)
        as well as `select_related` and `prefetch_related` models
        (with nested notation).

        Mandatory fields cannot be excluded as it will raise `ValidationError`,
        to exclude a field it has to be nullable.

        Pk column cannot be excluded - it's always auto added even
        if explicitly excluded.

        Actual call delegated to QuerySet.

        :param columns: columns to exclude
        :type columns: Union[List, str, Set, Dict]
        :return: QuerysetProxy
        :rtype: QuerysetProxy
        """
        queryset = self.queryset.exclude_fields(columns=columns)
        return self.__class__(
            relation=self.relation, type_=self.type_, to=self.to, qryset=queryset
        )

    def order_by(self, columns: Union[List, str, "OrderAction"]) -> "QuerysetProxy[T]":
        """
        With `order_by()` you can order the results from database based on your
        choice of fields.

        You can provide a string with field name or list of strings with fields names.

        Ordering in sql will be applied in order of names you provide in order_by.

        By default if you do not provide ordering `ormar` explicitly orders by
        all primary keys

        If you are sorting by nested models that causes that the result rows are
        unsorted by the main model `ormar` will combine those children rows into
        one main model.

        The main model will never duplicate in the result

        To order by main model field just provide a field name

        To sort on nested models separate field names with dunder '__'.

        You can sort this way across all relation types -> `ForeignKey`,
        reverse virtual FK and `ManyToMany` fields.

        To sort in descending order provide a hyphen in front of the field name

        Actual call delegated to QuerySet.

        :param columns: columns by which models should be sorted
        :type columns: Union[List, str]
        :return: QuerysetProxy
        :rtype: QuerysetProxy
        """
        queryset = self.queryset.order_by(columns)
        return self.__class__(
            relation=self.relation, type_=self.type_, to=self.to, qryset=queryset
        )

queryset: QuerySet[T] property writable

Returns queryset if it's set, AttributeError otherwise.

Returns:

Type	Description
QuerySet	QuerySet

all(*args, **kwargs) async

Returns all rows from a database for given model for set filter options.

Passing args and/or kwargs is a shortcut and equals to calling filter(*args, **kwargs).all().

If there are no rows meeting the criteria an empty list is returned.

Actual call delegated to QuerySet.

List of related models is cleared before the call.

Parameters:

Name	Type	Description	Default
kwargs	Any	fields names and proper value types	{}

Returns:

Type	Description
List[Model]	list of returned models

Source code in ormar\relations\querysetproxy.py

async def all(self, *args: Any, **kwargs: Any) -> List["T"]:  # noqa: A003
    """
    Returns all rows from a database for given model for set filter options.

    Passing args and/or kwargs is a shortcut and equals to calling
    `filter(*args, **kwargs).all()`.

    If there are no rows meeting the criteria an empty list is returned.

    Actual call delegated to QuerySet.

    List of related models is cleared before the call.

    :param kwargs: fields names and proper value types
    :type kwargs: Any
    :return: list of returned models
    :rtype: List[Model]
    """
    all_items = await self.queryset.all(*args, **kwargs)
    self._clean_items_on_load()
    self._register_related(all_items)
    return all_items

avg(columns) async

Returns avg value of columns for rows matching the given criteria (applied with filter and exclude if set before).

Returns:

Type	Description
Union[int, float, List]	avg value of columns

Source code in ormar\relations\querysetproxy.py

async def avg(self, columns: Union[str, List[str]]) -> Any:
    """
    Returns avg value of columns for rows matching the given criteria
    (applied with `filter` and `exclude` if set before).

    :return: avg value of columns
    :rtype: Union[int, float, List]
    """
    return await self.queryset.avg(columns=columns)

clear(keep_reversed=True) async

Removes all related models from given relation.

Removes all through models for m2m relation.

For reverse FK relations keep_reversed flag marks if the reversed models should be kept or deleted from the database too (False means that models will be deleted, and not only removed from relation).

Parameters:

Name	Type	Description	Default
keep_reversed	bool	flag if reverse models in reverse FK should be deleted or not, keep_reversed=False deletes them from database.	True

Returns:

Type	Description
int	number of deleted models

Source code in ormar\relations\querysetproxy.py

async def clear(self, keep_reversed: bool = True) -> int:
    """
    Removes all related models from given relation.

    Removes all through models for m2m relation.

    For reverse FK relations keep_reversed flag marks if the reversed models
    should be kept or deleted from the database too (False means that models
    will be deleted, and not only removed from relation).

    :param keep_reversed: flag if reverse models in reverse FK should be deleted
    or not, keep_reversed=False deletes them from database.
    :type keep_reversed: bool
    :return: number of deleted models
    :rtype: int
    """
    if self.type_ == ormar.RelationType.MULTIPLE:
        queryset = ormar.QuerySet(model_cls=self.relation.through)  # type: ignore
        owner_column = self._owner.get_name()
    else:
        queryset = ormar.QuerySet(model_cls=self.relation.to)  # type: ignore
        owner_column = self.related_field_name
    kwargs = {owner_column: self._owner}
    self._clean_items_on_load()
    if keep_reversed and self.type_ == ormar.RelationType.REVERSE:
        update_kwrgs = {f"{owner_column}": None}
        return await queryset.filter(_exclude=False, **kwargs).update(
            each=False, **update_kwrgs
        )
    return await queryset.delete(**kwargs)  # type: ignore

count(distinct=True) async

Returns number of rows matching the given criteria (applied with filter and exclude if set before). If distinct is True (the default), this will return the number of primary rows selected. If False, the count will be the total number of rows returned (including extra rows for one-to-many or many-to-many left select_related table joins). False is the legacy (buggy) behavior for workflows that depend on it.

Actual call delegated to QuerySet.

Parameters:

Name	Type	Description	Default
distinct	bool	flag if the primary table rows should be distinct or not	True

Returns:

Type	Description
int	number of rows

Source code in ormar\relations\querysetproxy.py

async def count(self, distinct: bool = True) -> int:
    """
    Returns number of rows matching the given criteria
    (applied with `filter` and `exclude` if set before).
    If `distinct` is `True` (the default), this will return
    the number of primary rows selected. If `False`,
    the count will be the total number of rows returned
    (including extra rows for `one-to-many` or `many-to-many`
    left `select_related` table joins).
    `False` is the legacy (buggy) behavior for workflows that depend on it.

    Actual call delegated to QuerySet.

    :param distinct: flag if the primary table rows should be distinct or not
    :return: number of rows
    :rtype: int
    """
    return await self.queryset.count(distinct=distinct)

create(**kwargs) async

Creates the model instance, saves it in a database and returns the updates model (with pk populated if not passed and autoincrement is set).

The allowed kwargs are Model fields names and proper value types.

For m2m relation the through model is created automatically.

Actual call delegated to QuerySet.

Parameters:

Name	Type	Description	Default
kwargs	Any	fields names and proper value types	{}

Returns:

Type	Description
Model	created model

Source code in ormar\relations\querysetproxy.py

async def create(self, **kwargs: Any) -> "T":
    """
    Creates the model instance, saves it in a database and returns the updates model
    (with pk populated if not passed and autoincrement is set).

    The allowed kwargs are `Model` fields names and proper value types.

    For m2m relation the through model is created automatically.

    Actual call delegated to QuerySet.

    :param kwargs: fields names and proper value types
    :type kwargs: Any
    :return: created model
    :rtype: Model
    """
    through_kwargs = kwargs.pop(self.through_model_name, {})
    if self.type_ == ormar.RelationType.REVERSE:
        kwargs[self.related_field_name] = self._owner
    created = await self.queryset.create(**kwargs)
    self._register_related(created)
    if self.type_ == ormar.RelationType.MULTIPLE:
        await self.create_through_instance(created, **through_kwargs)
    return created

create_through_instance(child, **kwargs) async

Crete a through model instance in the database for m2m relations.

Parameters:

Name	Type	Description	Default
kwargs	Any	dict of additional keyword arguments for through instance	{}
child	T	child model instance	required

Source code in ormar\relations\querysetproxy.py

async def create_through_instance(self, child: "T", **kwargs: Any) -> None:
    """
    Crete a through model instance in the database for m2m relations.

    :param kwargs: dict of additional keyword arguments for through instance
    :type kwargs: Any
    :param child: child model instance
    :type child: Model
    """
    model_cls = self.relation.through
    owner_column = self.related_field.default_target_field_name()  # type: ignore
    child_column = self.related_field.default_source_field_name()  # type: ignore
    rel_kwargs = {owner_column: self._owner.pk, child_column: child.pk}
    final_kwargs = {**rel_kwargs, **kwargs}
    if child.pk is None:
        raise ModelPersistenceError(
            f"You cannot save {child.get_name()} "
            f"model without primary key set! \n"
            f"Save the child model first."
        )
    await model_cls(**final_kwargs).save()

delete_through_instance(child) async

Removes through model instance from the database for m2m relations.

Parameters:

Name	Type	Description	Default
child	T	child model instance	required

Source code in ormar\relations\querysetproxy.py

async def delete_through_instance(self, child: "T") -> None:
    """
    Removes through model instance from the database for m2m relations.

    :param child: child model instance
    :type child: Model
    """
    queryset = ormar.QuerySet(model_cls=self.relation.through)  # type: ignore
    owner_column = self.related_field.default_target_field_name()  # type: ignore
    child_column = self.related_field.default_source_field_name()  # type: ignore
    kwargs = {owner_column: self._owner, child_column: child}
    link_instance = await queryset.filter(**kwargs).get()  # type: ignore
    await link_instance.delete()

exclude(*args, **kwargs)

Works exactly the same as filter and all modifiers (suffixes) are the same, but returns a not condition.

So if you use filter(name='John') which is where name = 'John' in SQL, the exclude(name='John') equals to where name <> 'John'

Note that all conditions are joined so if you pass multiple values it becomes a union of conditions.

exclude(name='John', age>=35) will become where not (name='John' and age>=35)

Actual call delegated to QuerySet.

Parameters:

Name	Type	Description	Default
kwargs	Any	fields names and proper value types	{}

Returns:

Type	Description
QuerysetProxy	filtered QuerysetProxy

Source code in ormar\relations\querysetproxy.py

def exclude(
    self, *args: Any, **kwargs: Any
) -> "QuerysetProxy[T]":  # noqa: A003, A001
    """
    Works exactly the same as filter and all modifiers (suffixes) are the same,
    but returns a *not* condition.

    So if you use `filter(name='John')` which is `where name = 'John'` in SQL,
    the `exclude(name='John')` equals to `where name <> 'John'`

    Note that all conditions are joined so if you pass multiple values it
    becomes a union of conditions.

    `exclude(name='John', age>=35)` will become
    `where not (name='John' and age>=35)`

    Actual call delegated to QuerySet.

    :param kwargs: fields names and proper value types
    :type kwargs: Any
    :return: filtered QuerysetProxy
    :rtype: QuerysetProxy
    """
    queryset = self.queryset.exclude(*args, **kwargs)
    return self.__class__(
        relation=self.relation, type_=self.type_, to=self.to, qryset=queryset
    )

exclude_fields(columns)

With exclude_fields() you can select subset of model columns that will be excluded to limit the data load.

It's the opposite of fields() method so check documentation above to see what options are available.

Especially check above how you can pass also nested dictionaries and sets as a mask to exclude fields from whole hierarchy.

Note that fields() and exclude_fields() works both for main models (on normal queries like get, all etc.) as well as select_related and prefetch_related models (with nested notation).

Mandatory fields cannot be excluded as it will raise ValidationError, to exclude a field it has to be nullable.

Pk column cannot be excluded - it's always auto added even if explicitly excluded.

Actual call delegated to QuerySet.

Parameters:

Name	Type	Description	Default
columns	Union[List, str, Set, Dict]	columns to exclude	required

Returns:

Type	Description
QuerysetProxy	QuerysetProxy

Source code in ormar\relations\querysetproxy.py

def exclude_fields(
    self, columns: Union[List, str, Set, Dict]
) -> "QuerysetProxy[T]":
    """
    With `exclude_fields()` you can select subset of model columns that will
    be excluded to limit the data load.

    It's the opposite of `fields()` method so check documentation above
    to see what options are available.

    Especially check above how you can pass also nested dictionaries
    and sets as a mask to exclude fields from whole hierarchy.

    Note that `fields()` and `exclude_fields()` works both for main models
    (on normal queries like `get`, `all` etc.)
    as well as `select_related` and `prefetch_related` models
    (with nested notation).

    Mandatory fields cannot be excluded as it will raise `ValidationError`,
    to exclude a field it has to be nullable.

    Pk column cannot be excluded - it's always auto added even
    if explicitly excluded.

    Actual call delegated to QuerySet.

    :param columns: columns to exclude
    :type columns: Union[List, str, Set, Dict]
    :return: QuerysetProxy
    :rtype: QuerysetProxy
    """
    queryset = self.queryset.exclude_fields(columns=columns)
    return self.__class__(
        relation=self.relation, type_=self.type_, to=self.to, qryset=queryset
    )

exists() async

Returns a bool value to confirm if there are rows matching the given criteria (applied with filter and exclude if set).

Actual call delegated to QuerySet.

Returns:

Type	Description
bool	result of the check

Source code in ormar\relations\querysetproxy.py

async def exists(self) -> bool:
    """
    Returns a bool value to confirm if there are rows matching the given criteria
    (applied with `filter` and `exclude` if set).

    Actual call delegated to QuerySet.

    :return: result of the check
    :rtype: bool
    """
    return await self.queryset.exists()

fields(columns)

With fields() you can select subset of model columns to limit the data load.

Note that fields() and exclude_fields() works both for main models (on normal queries like get, all etc.) as well as select_related and prefetch_related models (with nested notation).

You can select specified fields by passing a str, List[str], Set[str] or dict with nested definition.

To include related models use notation {related_name}__{column}[__{optional_next} etc.].

fields() can be called several times, building up the columns to select.

If you include related models into select_related() call but you won't specify columns for those models in fields - implies a list of all fields for those nested models.

Mandatory fields cannot be excluded as it will raise ValidationError, to exclude a field it has to be nullable.

Pk column cannot be excluded - it's always auto added even if not explicitly included.

You can also pass fields to include as dictionary or set.

To mark a field as included in a dictionary use it's name as key and ellipsis as value.

To traverse nested models use nested dictionaries.

To include fields at last level instead of nested dictionary a set can be used.

To include whole nested model specify model related field name and ellipsis.

Actual call delegated to QuerySet.

Parameters:

Name	Type	Description	Default
columns	Union[List, str, Set, Dict]	columns to include	required

Returns:

Type	Description
QuerysetProxy	QuerysetProxy

Source code in ormar\relations\querysetproxy.py

def fields(self, columns: Union[List, str, Set, Dict]) -> "QuerysetProxy[T]":
    """
    With `fields()` you can select subset of model columns to limit the data load.

    Note that `fields()` and `exclude_fields()` works both for main models
    (on normal queries like `get`, `all` etc.)
    as well as `select_related` and `prefetch_related`
    models (with nested notation).

    You can select specified fields by passing a `str, List[str], Set[str] or
    dict` with nested definition.

    To include related models use notation
    `{related_name}__{column}[__{optional_next} etc.]`.

    `fields()` can be called several times, building up the columns to select.

    If you include related models into `select_related()` call but you won't specify
    columns for those models in fields - implies a list of all fields for
    those nested models.

    Mandatory fields cannot be excluded as it will raise `ValidationError`,
     to exclude a field it has to be nullable.

    Pk column cannot be excluded - it's always auto added even if
    not explicitly included.

    You can also pass fields to include as dictionary or set.

    To mark a field as included in a dictionary use it's name as key
    and ellipsis as value.

    To traverse nested models use nested dictionaries.

    To include fields at last level instead of nested dictionary a set can be used.

    To include whole nested model specify model related field name and ellipsis.

    Actual call delegated to QuerySet.

    :param columns: columns to include
    :type columns: Union[List, str, Set, Dict]
    :return: QuerysetProxy
    :rtype: QuerysetProxy
    """
    queryset = self.queryset.fields(columns)
    return self.__class__(
        relation=self.relation, type_=self.type_, to=self.to, qryset=queryset
    )

filter(*args, **kwargs)

Allows you to filter by any Model attribute/field as well as to fetch instances, with a filter across an FK relationship.

You can use special filter suffix to change the filter operands:

• exact - like album__name__exact='Malibu' (exact match)
• iexact - like album__name__iexact='malibu' (exact match case insensitive)
• contains - like album__name__contains='Mal' (sql like)
• icontains - like album__name__icontains='mal' (sql like case insensitive)
• in - like album__name__in=['Malibu', 'Barclay'] (sql in)
• isnull - like album__name__isnull=True (sql is null) (isnotnull album__name__isnull=False (sql is not null))
• gt - like position__gt=3 (sql >)
• gte - like position__gte=3 (sql >=)
• lt - like position__lt=3 (sql <)
• lte - like position__lte=3 (sql <=)
• startswith - like album__name__startswith='Mal' (exact start match)
• istartswith - like album__name__istartswith='mal' (case insensitive)
• endswith - like album__name__endswith='ibu' (exact end match)
• iendswith - like album__name__iendswith='IBU' (case insensitive)

Actual call delegated to QuerySet.

Parameters:

Name	Type	Description	Default
kwargs	Any	fields names and proper value types	{}

Returns:

Type	Description
QuerysetProxy	filtered QuerysetProxy

Source code in ormar\relations\querysetproxy.py

def filter(  # noqa: A003, A001
    self, *args: Any, **kwargs: Any
) -> "QuerysetProxy[T]":
    """
    Allows you to filter by any `Model` attribute/field
    as well as to fetch instances, with a filter across an FK relationship.

    You can use special filter suffix to change the filter operands:

    *  exact - like `album__name__exact='Malibu'` (exact match)
    *  iexact - like `album__name__iexact='malibu'` (exact match case insensitive)
    *  contains - like `album__name__contains='Mal'` (sql like)
    *  icontains - like `album__name__icontains='mal'` (sql like case insensitive)
    *  in - like `album__name__in=['Malibu', 'Barclay']` (sql in)
    *  isnull - like `album__name__isnull=True` (sql is null)
       (isnotnull `album__name__isnull=False` (sql is not null))
    *  gt - like `position__gt=3` (sql >)
    *  gte - like `position__gte=3` (sql >=)
    *  lt - like `position__lt=3` (sql <)
    *  lte - like `position__lte=3` (sql <=)
    *  startswith - like `album__name__startswith='Mal'` (exact start match)
    *  istartswith - like `album__name__istartswith='mal'` (case insensitive)
    *  endswith - like `album__name__endswith='ibu'` (exact end match)
    *  iendswith - like `album__name__iendswith='IBU'` (case insensitive)

    Actual call delegated to QuerySet.

    :param kwargs: fields names and proper value types
    :type kwargs: Any
    :return: filtered QuerysetProxy
    :rtype: QuerysetProxy
    """
    queryset = self.queryset.filter(*args, **kwargs)
    return self.__class__(
        relation=self.relation, type_=self.type_, to=self.to, qryset=queryset
    )

first(*args, **kwargs) async

Gets the first row from the db ordered by primary key column ascending.

Actual call delegated to QuerySet.

Passing args and/or kwargs is a shortcut and equals to calling filter(*args, **kwargs).first().

List of related models is cleared before the call.

Parameters:

Name	Type	Description	Default
kwargs	Any		{}

Returns:

Type	Description
_asyncio.Future

Source code in ormar\relations\querysetproxy.py

async def first(self, *args: Any, **kwargs: Any) -> "T":
    """
    Gets the first row from the db ordered by primary key column ascending.

    Actual call delegated to QuerySet.

    Passing args and/or kwargs is a shortcut and equals to calling
    `filter(*args, **kwargs).first()`.

    List of related models is cleared before the call.

    :param kwargs:
    :type kwargs:
    :return:
    :rtype: _asyncio.Future
    """
    first = await self.queryset.first(*args, **kwargs)
    self._clean_items_on_load()
    self._register_related(first)
    return first

get(*args, **kwargs) async

Gets the first row from the db meeting the criteria set by kwargs.

If no criteria set it will return the last row in db sorted by pk.

Passing args and/or kwargs is a shortcut and equals to calling filter(*args, **kwargs).get().

Actual call delegated to QuerySet.

List of related models is cleared before the call.

Parameters:

Name	Type	Description	Default
kwargs	Any	fields names and proper value types	{}

Returns:

Type	Description
Model	returned model

Raises:

Type	Description
NoMatch	if no rows are returned
MultipleMatches	if more than 1 row is returned.

Source code in ormar\relations\querysetproxy.py

async def get(self, *args: Any, **kwargs: Any) -> "T":
    """
    Gets the first row from the db meeting the criteria set by kwargs.

    If no criteria set it will return the last row in db sorted by pk.

    Passing args and/or kwargs is a shortcut and equals to calling
    `filter(*args, **kwargs).get()`.

    Actual call delegated to QuerySet.

    List of related models is cleared before the call.

    :raises NoMatch: if no rows are returned
    :raises MultipleMatches: if more than 1 row is returned.
    :param kwargs: fields names and proper value types
    :type kwargs: Any
    :return: returned model
    :rtype: Model
    """
    get = await self.queryset.get(*args, **kwargs)
    self._clean_items_on_load()
    self._register_related(get)
    return get

get_or_create(_defaults=None, *args, **kwargs) async

Combination of create and get methods.

Tries to get a row meeting the criteria for kwargs and if NoMatch exception is raised it creates a new one with given kwargs and _defaults.

Parameters:

Name	Type	Description	Default
kwargs	Any	fields names and proper value types	{}
_defaults	Optional[Dict[str, Any]]	default values for creating object	None

Returns:

Type	Description
Tuple("T", bool)	model instance and a boolean

Source code in ormar\relations\querysetproxy.py

async def get_or_create(
    self,
    _defaults: Optional[Dict[str, Any]] = None,
    *args: Any,
    **kwargs: Any,
) -> Tuple["T", bool]:
    """
    Combination of create and get methods.

    Tries to get a row meeting the criteria for kwargs
    and if `NoMatch` exception is raised
    it creates a new one with given kwargs and _defaults.

    :param kwargs: fields names and proper value types
    :type kwargs: Any
    :param _defaults: default values for creating object
    :type _defaults: Optional[Dict[str, Any]]
    :return: model instance and a boolean
    :rtype: Tuple("T", bool)
    """
    try:
        return await self.get(*args, **kwargs), False
    except NoMatch:
        _defaults = _defaults or {}
        return await self.create(**{**kwargs, **_defaults}), True

get_or_none(*args, **kwargs) async

Gets the first row from the db meeting the criteria set by kwargs.

If no criteria set it will return the last row in db sorted by pk.

Passing args and/or kwargs is a shortcut and equals to calling filter(*args, **kwargs).get_or_none().

If not match is found None will be returned.

Parameters:

Name	Type	Description	Default
kwargs	Any	fields names and proper value types	{}

Returns:

Type	Description
Model	returned model

Source code in ormar\relations\querysetproxy.py

async def get_or_none(self, *args: Any, **kwargs: Any) -> Optional["T"]:
    """
    Gets the first row from the db meeting the criteria set by kwargs.

    If no criteria set it will return the last row in db sorted by pk.

    Passing args and/or kwargs is a shortcut and equals to calling
    `filter(*args, **kwargs).get_or_none()`.

    If not match is found None will be returned.

    :param kwargs: fields names and proper value types
    :type kwargs: Any
    :return: returned model
    :rtype: Model
    """
    try:
        get = await self.queryset.get(*args, **kwargs)
    except ormar.NoMatch:
        return None

    self._clean_items_on_load()
    self._register_related(get)
    return get

iterate(*args, **kwargs) async

Return async iterable generator for all rows from a database for given model.

Passing args and/or kwargs is a shortcut and equals to calling filter(*args, **kwargs).iterate().

If there are no rows meeting the criteria an empty async generator is returned.

Parameters:

Name	Type	Description	Default
kwargs	Any	fields names and proper value types	{}

Returns:

Type	Description
AsyncGenerator[Model]	asynchronous iterable generator of returned models

Source code in ormar\relations\querysetproxy.py

async def iterate(  # noqa: A003
    self,
    *args: Any,
    **kwargs: Any,
) -> AsyncGenerator["T", None]:
    """
    Return async iterable generator for all rows from a database for given model.

    Passing args and/or kwargs is a shortcut and equals to calling
    `filter(*args, **kwargs).iterate()`.

    If there are no rows meeting the criteria an empty async generator is returned.

    :param kwargs: fields names and proper value types
    :type kwargs: Any
    :return: asynchronous iterable generator of returned models
    :rtype: AsyncGenerator[Model]
    """

    async for item in self.queryset.iterate(*args, **kwargs):
        yield item

limit(limit_count)

You can limit the results to desired number of parent models.

Actual call delegated to QuerySet.

Parameters:

Name	Type	Description	Default
limit_count	int	number of models to limit	required

Returns:

Type	Description
QuerysetProxy	QuerysetProxy

Source code in ormar\relations\querysetproxy.py

def limit(self, limit_count: int) -> "QuerysetProxy[T]":
    """
    You can limit the results to desired number of parent models.

    Actual call delegated to QuerySet.

    :param limit_count: number of models to limit
    :type limit_count: int
    :return: QuerysetProxy
    :rtype: QuerysetProxy
    """
    queryset = self.queryset.limit(limit_count)
    return self.__class__(
        relation=self.relation, type_=self.type_, to=self.to, qryset=queryset
    )

max(columns) async

Returns max value of columns for rows matching the given criteria (applied with filter and exclude if set before).

Returns:

Type	Description
Any	max value of column(s)

Source code in ormar\relations\querysetproxy.py

async def max(self, columns: Union[str, List[str]]) -> Any:  # noqa: A003
    """
    Returns max value of columns for rows matching the given criteria
    (applied with `filter` and `exclude` if set before).

    :return: max value of column(s)
    :rtype: Any
    """
    return await self.queryset.max(columns=columns)

min(columns) async

Returns min value of columns for rows matching the given criteria (applied with filter and exclude if set before).

Returns:

Type	Description
Any	min value of column(s)

Source code in ormar\relations\querysetproxy.py

async def min(self, columns: Union[str, List[str]]) -> Any:  # noqa: A003
    """
    Returns min value of columns for rows matching the given criteria
    (applied with `filter` and `exclude` if set before).

    :return: min value of column(s)
    :rtype: Any
    """
    return await self.queryset.min(columns=columns)

offset(offset)

You can also offset the results by desired number of main models.

Actual call delegated to QuerySet.

Parameters:

Name	Type	Description	Default
offset	int	numbers of models to offset	required

Returns:

Type	Description
QuerysetProxy	QuerysetProxy

Source code in ormar\relations\querysetproxy.py

def offset(self, offset: int) -> "QuerysetProxy[T]":
    """
    You can also offset the results by desired number of main models.

    Actual call delegated to QuerySet.

    :param offset: numbers of models to offset
    :type offset: int
    :return: QuerysetProxy
    :rtype: QuerysetProxy
    """
    queryset = self.queryset.offset(offset)
    return self.__class__(
        relation=self.relation, type_=self.type_, to=self.to, qryset=queryset
    )

order_by(columns)

With order_by() you can order the results from database based on your choice of fields.

You can provide a string with field name or list of strings with fields names.

Ordering in sql will be applied in order of names you provide in order_by.

By default if you do not provide ordering ormar explicitly orders by all primary keys

If you are sorting by nested models that causes that the result rows are unsorted by the main model ormar will combine those children rows into one main model.

The main model will never duplicate in the result

To order by main model field just provide a field name

To sort on nested models separate field names with dunder '__'.

You can sort this way across all relation types -> ForeignKey, reverse virtual FK and ManyToMany fields.

To sort in descending order provide a hyphen in front of the field name

Actual call delegated to QuerySet.

Parameters:

Name	Type	Description	Default
columns	Union[List, str, OrderAction]	columns by which models should be sorted	required

Returns:

Type	Description
QuerysetProxy	QuerysetProxy

Source code in ormar\relations\querysetproxy.py

def order_by(self, columns: Union[List, str, "OrderAction"]) -> "QuerysetProxy[T]":
    """
    With `order_by()` you can order the results from database based on your
    choice of fields.

    You can provide a string with field name or list of strings with fields names.

    Ordering in sql will be applied in order of names you provide in order_by.

    By default if you do not provide ordering `ormar` explicitly orders by
    all primary keys

    If you are sorting by nested models that causes that the result rows are
    unsorted by the main model `ormar` will combine those children rows into
    one main model.

    The main model will never duplicate in the result

    To order by main model field just provide a field name

    To sort on nested models separate field names with dunder '__'.

    You can sort this way across all relation types -> `ForeignKey`,
    reverse virtual FK and `ManyToMany` fields.

    To sort in descending order provide a hyphen in front of the field name

    Actual call delegated to QuerySet.

    :param columns: columns by which models should be sorted
    :type columns: Union[List, str]
    :return: QuerysetProxy
    :rtype: QuerysetProxy
    """
    queryset = self.queryset.order_by(columns)
    return self.__class__(
        relation=self.relation, type_=self.type_, to=self.to, qryset=queryset
    )

paginate(page, page_size=20)

You can paginate the result which is a combination of offset and limit clauses. Limit is set to page size and offset is set to (page-1) * page_size.

Actual call delegated to QuerySet.

Parameters:

Name	Type	Description	Default
page_size	int	numbers of items per page	20
page	int	page number	required

Returns:

Type	Description
QuerySet	QuerySet

Source code in ormar\relations\querysetproxy.py

def paginate(self, page: int, page_size: int = 20) -> "QuerysetProxy[T]":
    """
    You can paginate the result which is a combination of offset and limit clauses.
    Limit is set to page size and offset is set to (page-1) * page_size.

    Actual call delegated to QuerySet.

    :param page_size: numbers of items per page
    :type page_size: int
    :param page: page number
    :type page: int
    :return: QuerySet
    :rtype: QuerySet
    """
    queryset = self.queryset.paginate(page=page, page_size=page_size)
    return self.__class__(
        relation=self.relation, type_=self.type_, to=self.to, qryset=queryset
    )

prefetch_related(related)

Allows to prefetch related models during query - but opposite to select_related each subsequent model is fetched in a separate database query.

With prefetch_related always one query per Model is run against the database, meaning that you will have multiple queries executed one after another.

To fetch related model use ForeignKey names.

To chain related Models relation use double underscores between names.

Actual call delegated to QuerySet.

Parameters:

Name	Type	Description	Default
related	Union[List, str]	list of relation field names, can be linked by '__' to nest	required

Returns:

Type	Description
QuerysetProxy	QuerysetProxy

Source code in ormar\relations\querysetproxy.py

def prefetch_related(self, related: Union[List, str]) -> "QuerysetProxy[T]":
    """
    Allows to prefetch related models during query - but opposite to
    `select_related` each subsequent model is fetched in a separate database query.

    **With `prefetch_related` always one query per Model is run against the
    database**, meaning that you will have multiple queries executed one
    after another.

    To fetch related model use `ForeignKey` names.

    To chain related `Models` relation use double underscores between names.

    Actual call delegated to QuerySet.

    :param related: list of relation field names, can be linked by '__' to nest
    :type related: Union[List, str]
    :return: QuerysetProxy
    :rtype: QuerysetProxy
    """
    queryset = self.queryset.prefetch_related(related)
    return self.__class__(
        relation=self.relation, type_=self.type_, to=self.to, qryset=queryset
    )

select_all(follow=False)

By default adds only directly related models.

If follow=True is set it adds also related models of related models.

To not get stuck in an infinite loop as related models also keep a relation to parent model visited models set is kept.

That way already visited models that are nested are loaded, but the load do not follow them inside. So Model A -> Model B -> Model C -> Model A -> Model X will load second Model A but will never follow into Model X. Nested relations of those kind need to be loaded manually.

Parameters:

Name	Type	Description	Default
follow	bool	flag to trigger deep save - by default only directly related models are saved with follow=True also related models of related models are saved	False

Returns:

Type	Description
Model	reloaded Model

Source code in ormar\relations\querysetproxy.py

def select_all(self, follow: bool = False) -> "QuerysetProxy[T]":
    """
    By default adds only directly related models.

    If follow=True is set it adds also related models of related models.

    To not get stuck in an infinite loop as related models also keep a relation
    to parent model visited models set is kept.

    That way already visited models that are nested are loaded, but the load do not
    follow them inside. So Model A -> Model B -> Model C -> Model A -> Model X
    will load second Model A but will never follow into Model X.
    Nested relations of those kind need to be loaded manually.

    :param follow: flag to trigger deep save -
    by default only directly related models are saved
    with follow=True also related models of related models are saved
    :type follow: bool
    :return: reloaded Model
    :rtype: Model
    """
    queryset = self.queryset.select_all(follow=follow)
    return self.__class__(
        relation=self.relation, type_=self.type_, to=self.to, qryset=queryset
    )

select_related(related)

Allows to prefetch related models during the same query.

With select_related always only one query is run against the database, meaning that one (sometimes complicated) join is generated and later nested models are processed in python.

To fetch related model use ForeignKey names.

To chain related Models relation use double underscores between names.

Actual call delegated to QuerySet.

Parameters:

Name	Type	Description	Default
related	Union[List, str]	list of relation field names, can be linked by '__' to nest	required

Returns:

Type	Description
QuerysetProxy	QuerysetProxy

Source code in ormar\relations\querysetproxy.py

def select_related(self, related: Union[List, str]) -> "QuerysetProxy[T]":
    """
    Allows to prefetch related models during the same query.

    **With `select_related` always only one query is run against the database**,
    meaning that one (sometimes complicated) join is generated and later nested
    models are processed in python.

    To fetch related model use `ForeignKey` names.

    To chain related `Models` relation use double underscores between names.

    Actual call delegated to QuerySet.

    :param related: list of relation field names, can be linked by '__' to nest
    :type related: Union[List, str]
    :return: QuerysetProxy
    :rtype: QuerysetProxy
    """
    queryset = self.queryset.select_related(related)
    return self.__class__(
        relation=self.relation, type_=self.type_, to=self.to, qryset=queryset
    )

sum(columns) async

Returns sum value of columns for rows matching the given criteria (applied with filter and exclude if set before).

Returns:

Type	Description
int	sum value of columns

Source code in ormar\relations\querysetproxy.py

async def sum(self, columns: Union[str, List[str]]) -> Any:  # noqa: A003
    """
    Returns sum value of columns for rows matching the given criteria
    (applied with `filter` and `exclude` if set before).

    :return: sum value of columns
    :rtype: int
    """
    return await self.queryset.sum(columns=columns)

update(each=False, **kwargs) async

Updates the model table after applying the filters from kwargs.

You have to either pass a filter to narrow down a query or explicitly pass each=True flag to affect whole table.

Parameters:

Name	Type	Description	Default
each	bool	flag if whole table should be affected if no filter is passed	False
kwargs	Any	fields names and proper value types	{}

Returns:

Type	Description
int	number of updated rows

Source code in ormar\relations\querysetproxy.py

async def update(self, each: bool = False, **kwargs: Any) -> int:
    """
    Updates the model table after applying the filters from kwargs.

    You have to either pass a filter to narrow down a query or explicitly pass
    each=True flag to affect whole table.

    :param each: flag if whole table should be affected if no filter is passed
    :type each: bool
    :param kwargs: fields names and proper value types
    :type kwargs: Any
    :return: number of updated rows
    :rtype: int
    """
    # queryset proxy always have one filter for pk of parent model
    if (
        not each
        and (len(self.queryset.filter_clauses) + len(self.queryset.exclude_clauses))
        == 1
    ):
        raise QueryDefinitionError(
            "You cannot update without filtering the queryset first. "
            "If you want to update all rows use update(each=True, **kwargs)"
        )

    through_kwargs = kwargs.pop(self.through_model_name, {})
    children = await self.queryset.all()
    for child in children:
        await child.update(**kwargs)  # type: ignore
        if self.type_ == ormar.RelationType.MULTIPLE and through_kwargs:
            await self.update_through_instance(
                child=child, **through_kwargs  # type: ignore
            )
    return len(children)

update_or_create(**kwargs) async

Updates the model, or in case there is no match in database creates a new one.

Actual call delegated to QuerySet.

Parameters:

Name	Type	Description	Default
kwargs	Any	fields names and proper value types	{}

Returns:

Type	Description
Model	updated or created model

Source code in ormar\relations\querysetproxy.py

async def update_or_create(self, **kwargs: Any) -> "T":
    """
    Updates the model, or in case there is no match in database creates a new one.

    Actual call delegated to QuerySet.

    :param kwargs: fields names and proper value types
    :type kwargs: Any
    :return: updated or created model
    :rtype: Model
    """
    pk_name = self.queryset.model_meta.pkname
    if "pk" in kwargs:
        kwargs[pk_name] = kwargs.pop("pk")
    if pk_name not in kwargs or kwargs.get(pk_name) is None:
        return await self.create(**kwargs)
    model = await self.queryset.get(pk=kwargs[pk_name])
    return await model.update(**kwargs)

update_through_instance(child, **kwargs) async

Updates a through model instance in the database for m2m relations.

Parameters:

Name	Type	Description	Default
kwargs	Any	dict of additional keyword arguments for through instance	{}
child	T	child model instance	required

Source code in ormar\relations\querysetproxy.py

async def update_through_instance(self, child: "T", **kwargs: Any) -> None:
    """
    Updates a through model instance in the database for m2m relations.

    :param kwargs: dict of additional keyword arguments for through instance
    :type kwargs: Any
    :param child: child model instance
    :type child: Model
    """
    model_cls = self.relation.through
    owner_column = self.related_field.default_target_field_name()  # type: ignore
    child_column = self.related_field.default_source_field_name()  # type: ignore
    rel_kwargs = {owner_column: self._owner.pk, child_column: child.pk}
    through_model = await model_cls.objects.get(**rel_kwargs)
    await through_model.update(**kwargs)

upsert_through_instance(child, **kwargs) async

Updates a through model instance in the database for m2m relations if it already exists, else creates one.

Parameters:

Name	Type	Description	Default
kwargs	Any	dict of additional keyword arguments for through instance	{}
child	T	child model instance	required

Source code in ormar\relations\querysetproxy.py

async def upsert_through_instance(self, child: "T", **kwargs: Any) -> None:
    """
    Updates a through model instance in the database for m2m relations if
    it already exists, else creates one.

    :param kwargs: dict of additional keyword arguments for through instance
    :type kwargs: Any
    :param child: child model instance
    :type child: Model
    """
    try:
        await self.update_through_instance(child=child, **kwargs)
    except NoMatch:
        await self.create_through_instance(child=child, **kwargs)

values(fields=None, exclude_through=False) async

Return a list of dictionaries with column values in order of the fields passed or all fields from queried models.

To filter for given row use filter/exclude methods before values, to limit number of rows use limit/offset or paginate before values.

Note that it always return a list even for one row from database.

Parameters:

Name	Type	Description	Default
exclude_through	bool	flag if through models should be excluded	False
fields	Union[List, str, Set, Dict]	field name or list of field names to extract from db	None

Source code in ormar\relations\querysetproxy.py

async def values(
    self, fields: Union[List, str, Set, Dict] = None, exclude_through: bool = False
) -> List:
    """
    Return a list of dictionaries with column values in order of the fields
    passed or all fields from queried models.

    To filter for given row use filter/exclude methods before values,
    to limit number of rows use limit/offset or paginate before values.

    Note that it always return a list even for one row from database.

    :param exclude_through: flag if through models should be excluded
    :type exclude_through: bool
    :param fields: field name or list of field names to extract from db
    :type fields:  Union[List, str, Set, Dict]
    """
    return await self.queryset.values(
        fields=fields, exclude_through=exclude_through
    )

values_list(fields=None, flatten=False, exclude_through=False) async

Return a list of tuples with column values in order of the fields passed or all fields from queried models.

When one field is passed you can flatten the list of tuples into list of values of that single field.

To filter for given row use filter/exclude methods before values, to limit number of rows use limit/offset or paginate before values.

Note that it always return a list even for one row from database.

Parameters:

Name	Type	Description	Default
exclude_through	bool	flag if through models should be excluded	False
fields	Union[List, str, Set, Dict]	field name or list of field names to extract from db	None
flatten	bool	when one field is passed you can flatten the list of tuples	False

Source code in ormar\relations\querysetproxy.py

async def values_list(
    self,
    fields: Union[List, str, Set, Dict] = None,
    flatten: bool = False,
    exclude_through: bool = False,
) -> List:
    """
    Return a list of tuples with column values in order of the fields passed or
    all fields from queried models.

    When one field is passed you can flatten the list of tuples into list of values
    of that single field.

    To filter for given row use filter/exclude methods before values,
    to limit number of rows use limit/offset or paginate before values.

    Note that it always return a list even for one row from database.

    :param exclude_through: flag if through models should be excluded
    :type exclude_through: bool
    :param fields: field name or list of field names to extract from db
    :type fields: Union[str, List[str]]
    :param flatten: when one field is passed you can flatten the list of tuples
    :type flatten: bool
    """
    return await self.queryset.values(
        fields=fields,
        exclude_through=exclude_through,
        _as_dict=False,
        _flatten=flatten,
    )