DistanceField

Wrapper for Distance values.

Attributes

Attribute	Type	Description
geo_field	models.Field	The geographic field associated with this distance calculation, used to determine the appropriate unit attributes from the database connection.

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Constructor

Signature

def DistanceField(
    geo_field: django.contrib.gis.db.models.fields.Field
) - > null

Parameters

Name	Type	Description
geo_field	django.contrib.gis.db.models.fields.Field	The geographic field associated with this distance measurement.

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Methods

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get_prep_value()

@classmethod
def get_prep_value(
    value: any
) - > Distance|float|null

Prepares the value for use in a query by ensuring Distance objects are handled correctly before being passed to the database driver.

Parameters

Name	Type	Description
value	any	The value to be prepared for a database query, typically a Distance object or a numeric type.

Returns

Type	Description
`Distance	float

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get_db_prep_value()

@classmethod
def get_db_prep_value(
    value: any,
    connection: DatabaseConnection,
    prepared: boolean = False
) - > float|any

Converts a Distance object into a raw database value using the unit attribute appropriate for the associated geographic field.

Parameters

Name	Type	Description
value	any	The value to be converted for the database.
connection	DatabaseConnection	The current database connection object used to determine unit attributes.
prepared	boolean = False	Whether the value has already been passed through get_prep_value.

Returns

Type	Description
`float	any`

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from_db_value()

@classmethod
def from_db_value(
    value: float|null,
    expression: [Expression](../../../../../../db/models/expressions/expression.md?sid=django_db_models_expressions_expression),
    connection: DatabaseConnection
) - > Distance|float|null

Converts the raw database numeric value back into a Distance object using the units defined by the database backend.

Parameters

Name	Type	Description
value	`float	null`
expression	[Expression](../../../../../../db/models/expressions/expression.md?sid=django_db_models_expressions_expression)	The query expression that produced the value.
connection	DatabaseConnection	The current database connection used to resolve distance unit attributes.

Returns

Type	Description
`Distance	float

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get_internal_type()

@classmethod
def get_internal_type() - > string

Returns the internal name of the field type for Django's model introspection.

Returns

Type	Description
string	The string identifier "DistanceField" used by the framework.

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