Alexander Hess
fdcc93a1ea
- use SQLAlchemy (and PostgreSQL) to model the ORM layer
- add the following models:
+ Address => modelling all kinds of addresses
+ City => model the three target cities
+ Courier => model the UDP's couriers
+ Customer => model the UDP's customers
+ Order => model the orders received by the UDP
+ Restaurant => model the restaurants active on the UDP
- so far, the emphasis lies on expression the Foreign Key
and Check Constraints that are used to validate the assumptions
inherent to the cleanded data
- provide database-independent unit tests with 100% coverage
- provide additional integration tests ("e2e") that commit data to
a PostgreSQL instance to validate that the constraints work
- adapt linting rules a bit
82 lines
3 KiB
Python
82 lines
3 KiB
Python
"""Provide the ORM's Address model."""
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import sqlalchemy as sa
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from sqlalchemy import orm
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from sqlalchemy.dialects import postgresql
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from sqlalchemy.ext import hybrid
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from urban_meal_delivery.db import meta
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class Address(meta.Base):
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"""An Address of a Customer or a Restaurant on the UDP."""
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__tablename__ = 'addresses'
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# Columns
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id = sa.Column(sa.Integer, primary_key=True, autoincrement=False) # noqa:WPS125
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_primary_id = sa.Column('primary_id', sa.Integer, nullable=False, index=True)
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created_at = sa.Column(sa.DateTime, nullable=False)
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place_id = sa.Column(
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sa.Unicode(length=120), nullable=False, index=True, # noqa:WPS432
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)
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latitude = sa.Column(postgresql.DOUBLE_PRECISION, nullable=False)
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longitude = sa.Column(postgresql.DOUBLE_PRECISION, nullable=False)
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_city_id = sa.Column('city_id', sa.SmallInteger, nullable=False, index=True)
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city_name = sa.Column('city', sa.Unicode(length=25), nullable=False) # noqa:WPS432
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zip_code = sa.Column(sa.Integer, nullable=False, index=True)
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street = sa.Column(sa.Unicode(length=80), nullable=False) # noqa:WPS432
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floor = sa.Column(sa.SmallInteger)
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# Constraints
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__table_args__ = (
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sa.ForeignKeyConstraint(
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['primary_id'], ['addresses.id'], onupdate='RESTRICT', ondelete='RESTRICT',
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),
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sa.ForeignKeyConstraint(
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['city_id'], ['cities.id'], onupdate='RESTRICT', ondelete='RESTRICT',
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),
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sa.CheckConstraint(
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'-90 <= latitude AND latitude <= 90', name='latitude_between_90_degrees',
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),
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sa.CheckConstraint(
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'-180 <= longitude AND longitude <= 180',
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name='longitude_between_180_degrees',
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),
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sa.CheckConstraint(
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'30000 <= zip_code AND zip_code <= 99999', name='valid_zip_code',
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),
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sa.CheckConstraint('0 <= floor AND floor <= 40', name='realistic_floor'),
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)
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# Relationships
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city = orm.relationship('City', back_populates='addresses')
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restaurant = orm.relationship('Restaurant', back_populates='address', uselist=False)
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orders_picked_up = orm.relationship(
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'Order',
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back_populates='pickup_address',
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foreign_keys='[Order._pickup_address_id]',
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)
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orders_delivered = orm.relationship(
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'Order',
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back_populates='delivery_address',
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foreign_keys='[Order._delivery_address_id]',
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)
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def __repr__(self) -> str:
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"""Non-literal text representation."""
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return '<{cls}({street} in {city})>'.format(
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cls=self.__class__.__name__, street=self.street, city=self.city_name,
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)
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@hybrid.hybrid_property
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def is_primary(self) -> bool:
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"""If an Address object is the earliest one entered at its location.
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Street addresses may have been entered several times with different
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versions/spellings of the street name and/or different floors.
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`is_primary` indicates the first in a group of addresses.
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"""
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return self.id == self._primary_id
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