BaseModelFormSet

A FormSet for editing a queryset and/or adding new objects to it.

Attributes

Attribute	Type	Description
model	Model class = null	The Django model class that this formset is responsible for editing and creating.
edit_only	boolean = false	A boolean flag that, when set to True, prevents the formset from saving any new objects and only allows modifications to existing ones.
unique_fields	set = set()	Set of fields that must be unique among forms of this set.

---

Constructor

Signature

def BaseModelFormSet(
    data: dict = None,
    files: dict = None,
    auto_id: string = id_%s,
    prefix: string = None,
    queryset: [QuerySet](../../db/models/query/queryset.md?sid=django_db_models_query_queryset) = None,
    initial: list = None,
    kwargs: dict
)

Parameters

Name	Type	Description
data	dict = None	A dictionary of data used to bind the formset.
files	dict = None	A dictionary of uploaded file data.
auto_id	string = id_%s	The format string used to generate the HTML 'id' attribute for form fields.
prefix	string = None	A prefix to be applied to the name of every field in the formset.
queryset	[QuerySet](../../db/models/query/queryset.md?sid=django_db_models_query_queryset) = None	The QuerySet of model instances to be used in the formset.
initial	list = None	A list of dictionaries containing initial data for extra forms.
kwargs	dict	Additional keyword arguments passed to the parent BaseFormSet class.

---

Methods

---

initial_form_count()

@classmethod
def initial_form_count() - > int

Return the number of forms that are required in this FormSet.

Returns

Type	Description
int	The count of forms representing existing objects in the queryset or the base formset count.

---

get_queryset()

@classmethod
def get_queryset() - > [QuerySet](../../db/models/query/queryset.md?sid=django_db_models_query_queryset)

Returns the queryset of objects to be edited by the formset, applying default ordering if necessary to ensure consistency.

Returns

Type	Description
[QuerySet](../../db/models/query/queryset.md?sid=django_db_models_query_queryset)	The queryset containing the objects managed by this formset.

---

save_new()

@classmethod
def save_new(
    form: [ModelForm](modelform.md?sid=django_forms_models_modelform),
    commit: bool = True
) - > [Model](../../db/models/base/model.md?sid=django_db_models_base_model)

Save and return a new model instance for the given form.

Parameters

Name	Type	Description
form	[ModelForm](modelform.md?sid=django_forms_models_modelform)	The form containing data for the new object.
commit	bool = True	Whether to persist the changes to the database immediately.

Returns

Type	Description
[Model](../../db/models/base/model.md?sid=django_db_models_base_model)	The newly created and saved model instance.

---

save_existing()

@classmethod
def save_existing(
    form: [ModelForm](modelform.md?sid=django_forms_models_modelform),
    obj: [Model](../../db/models/base/model.md?sid=django_db_models_base_model),
    commit: bool = True
) - > [Model](../../db/models/base/model.md?sid=django_db_models_base_model)

Save and return an existing model instance for the given form.

Parameters

Name	Type	Description
form	[ModelForm](modelform.md?sid=django_forms_models_modelform)	The form containing updated data for the object.
obj	[Model](../../db/models/base/model.md?sid=django_db_models_base_model)	The existing model instance to be updated.
commit	bool = True	Whether to persist the changes to the database immediately.

Returns

Type	Description
[Model](../../db/models/base/model.md?sid=django_db_models_base_model)	The updated model instance.

---

delete_existing()

@classmethod
def delete_existing(
    obj: [Model](../../db/models/base/model.md?sid=django_db_models_base_model),
    commit: bool = True
) - > null

Deletes an existing model instance.

Parameters

Name	Type	Description
obj	[Model](../../db/models/base/model.md?sid=django_db_models_base_model)	The model instance to be deleted from the database.
commit	bool = True	Whether to execute the deletion immediately.

Returns

Type	Description
null	null

---

save()

@classmethod
def save(
    commit: bool = True
) - > list

Save model instances for every form, adding and changing instances as necessary, and return the list of instances.

Parameters

Name	Type	Description
commit	bool = True	Whether to persist changes to the database; if False, adds a save_m2m method to the formset.

Returns

Type	Description
list	A list of all model instances that were created or updated.

---

clean()

@classmethod
def clean() - > null

Hook for performing additional validation on the formset; currently triggers uniqueness validation across all forms.

Returns

Type	Description
null	null

---

validate_unique()

@classmethod
def validate_unique() - > null

Validates that the data across all forms satisfies model uniqueness constraints and date-based uniqueness constraints.

Returns

Type	Description
null	null

---

get_unique_error_message()

@classmethod
def get_unique_error_message(
    unique_check: tuple
) - > string

Constructs an error message for a failed uniqueness check involving one or more fields.

Parameters

Name	Type	Description
unique_check	tuple	A collection of field names that failed the uniqueness validation.

Returns

Type	Description
string	A localized error message describing the duplicate field data.

---

get_date_error_message()

@classmethod
def get_date_error_message(
    date_check: tuple
) - > string

Constructs an error message for a failed unique_for_date (or month/year) constraint.

Parameters

Name	Type	Description
date_check	tuple	A tuple containing the model class, lookup type, field name, and date field name.

Returns

Type	Description
string	A localized error message describing the date-based uniqueness conflict.

---

get_form_error()

@classmethod
def get_form_error() - > string

Returns the generic error message used for forms that contain duplicate values.

Returns

Type	Description
string	A localized string instructing the user to correct duplicate values.

---

save_existing_objects()

@classmethod
def save_existing_objects(
    commit: bool = True
) - > list

Updates or deletes objects that were already present in the queryset based on form data.

Parameters

Name	Type	Description
commit	bool = True	Whether to persist updates and deletions to the database.

Returns

Type	Description
list	A list of existing model instances that were updated.

---

save_new_objects()

@classmethod
def save_new_objects(
    commit: bool = True
) - > list

Creates and saves new model instances from the extra forms in the formset that have changed.

Parameters

Name	Type	Description
commit	bool = True	Whether to persist the new objects to the database.

Returns

Type	Description
list	A list of the newly created model instances.

---

add_fields()

@classmethod
def add_fields(
    form: [ModelForm](modelform.md?sid=django_forms_models_modelform),
    index: int|null
) - > null

Add a hidden field for the object's primary key.

Parameters

Name	Type	Description
form	[ModelForm](modelform.md?sid=django_forms_models_modelform)	The form instance to which the primary key field should be added.
index	`int	null`

Returns

Type	Description
null	null

---