Hello, My applications does some ordering using the distance from latitude
and longitude haversine distance, i was able to calculate this using
@hybrid.method and @.*expression, but i can't output the calculated
distance:
*class PartnerAddress(db.Model, WithTimestampsModel, SerializeMixin):*
* # Columns*
* id = db.Column(db.Integer(), primary_key=True, nullable=False)*
* partner_id = db.Column(*
* db.Integer(),*
* db.ForeignKey('partner.id'),*
* nullable=False*
* )*
* latitude = db.Column(db.Numeric(precision=9, scale=7), nullable=False)*
* longitude = db.Column(db.Numeric(precision=10, scale=7),
nullable=False)*
* @hybrid_method*
* def distance(self, lat, lng):*
* return math.acos(math.cos(math.radians(self.latitude)) *
math.cos(math.radians(lat)) **
* math.cos(math.radians(self.longitude) - math.radians(lng))
+*
* math.sin(math.radians(self.latitude)) *
math.sin(math.radians(lat))) * 6371*
* @distance.expression*
* def distance(cls, lat, lng):*
* return func.acos(func.cos(func.radians(cls.latitude)) *
func.cos(func.radians(lat)) **
* func.cos(func.radians(lng) -
func.radians(cls.longitude)) +*
* func.sin(func.radians(cls.latitude)) *
func.sin(func.radians(lat))) * 6371*
*class PartnerV3(db.Model, WithTimestampsModel,*
* SoftDeletableModel, SerializeMixin):*
* name = db.Column(db.String(128), nullable=False)*
* address = db.relationship(*
* 'mustafar.partner.v3.models.address.PartnerAddress',*
* backref='partner',*
* uselist=False*
* )*
when querying like this:
query =
PartnerV3.query.join(PartnerAddress).order_by(PartnerAddress.distance(lat,
lng)).paginate(1,10, False)
I can paginate the result, but it returns only the PartnerV3 object, i
can't access the distance.
How do I access this distance property?
--
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http://www.sqlalchemy.org/
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