deb-python-sqlalchemy-utils/docs/index.rst

SQLAlchemy-Utils

SQLAlchemy-Utils provides custom data types and various utility functions for SQLAlchemy.

Using automatic data coercion

SQLAlchemy-Utils provides various new data types for SQLAlchemy and in order to gain full advantage of these datatypes you should use coercion_listener. Setting up the listener is easy:

import sqlalchemy as sa
from sqlalchemy_utils import coercion_listener


sa.event.listen(sa.orm.mapper, 'mapper_configured', coercion_listener)

The listener automatically detects SQLAlchemy-Utils compatible data types and coerces all attributes using these types to appropriate objects.

Example :

from colour import Color
from sqlalchemy_utils import ColorType


class Document(Base):
    __tablename__ = 'player'
    id = db.Column(db.Integer, autoincrement=True)
    name = db.Column(db.Unicode(50))
    background_color = db.Column(ColorType)


document = Document()
document.background_color = 'F5F5F5'
document.background_color  # Color object
session.commit()

ScalarListType

ScalarListType type provides convenient way for saving multiple scalar values in one column. ScalarListType works like list on python side and saves the result as comma-separated list in the database (custom separators can also be used).

Example :

from sqlalchemy_utils import ScalarListType


class User(Base):
    __tablename__ = 'user'
    id = db.Column(db.Integer, autoincrement=True)
    hobbies = db.Column(ScalarListType())


user = User()
user.hobbies = [u'football', u'ice_hockey']
session.commit()

You can easily set up integer lists too:

:

from sqlalchemy_utils import ScalarListType


class Player(Base):
    __tablename__ = 'player'
    id = db.Column(db.Integer, autoincrement=True)
    points = db.Column(ScalarListType(int))


player = Player()
player.points = [11, 12, 8, 80]
session.commit()

ColorType

ColorType provides a way for saving Color (from colour package) objects into database. ColorType saves Color objects as strings on the way in and converts them back to objects when querying the database.

:

from colour import Color
from sqlalchemy_utils import ColorType


class Document(Base):
    __tablename__ = 'player'
    id = db.Column(db.Integer, autoincrement=True)
    name = db.Column(db.Unicode(50))
    background_color = db.Column(ColorType)


document = Document()
document.background_color = Color('#F5F5F5')
session.commit()

Querying the database returns Color objects:

document = session.query(Document).first()

document.background_color.hex
# '#f5f5f5'

For more information about colour package and Color object, see https://github.com/vaab/colour

NumberRangeType

NumberRangeType provides way for saving range of numbers into database.

Example :

from sqlalchemy_utils import NumberRangeType, NumberRange


class Event(Base):
    __tablename__ = 'user'
    id = db.Column(db.Integer, autoincrement=True)
    name = db.Column(db.Unicode(255))
    estimated_number_of_persons = db.Column(NumberRangeType)


party = Event(name=u'party')

# we estimate the party to contain minium of 10 persons and at max
# 100 persons
party.estimated_number_of_persons = NumberRange(10, 100)

print party.estimated_number_of_persons
# '10-100'

NumberRange supports some arithmetic operators: :

meeting = Event(name=u'meeting')

meeting.estimated_number_of_persons = NumberRange(20, 40)

total = (
    meeting.estimated_number_of_persons +
    party.estimated_number_of_persons
)
print total
# '30-140'

UUIDType

UUIDType will store a UUID in the database in a native format, if available, or a 16-byte BINARY column or a 32-character CHAR column if not.

from sqlalchemy_utils import UUIDType
import uuid

class User(Base):
    __tablename__ = 'user'

    # Pass `binary=False` to fallback to CHAR instead of BINARY
    id = sa.Column(UUIDType(binary=False), primary_key=True)

TimezoneType

TimezoneType provides a way for saving timezones (from either the pytz or the dateutil package) objects into database. TimezoneType saves timezone objects as strings on the way in and converts them back to objects when querying the database.

from sqlalchemy_utils import UUIDType

class User(Base):
    __tablename__ = 'user'

    # Pass backend='pytz' to change it to use pytz (dateutil by default)
    timezone = sa.Column(TimezoneType(backend='pytz'))

API Documentation

sqlalchemy_utils

InstrumentedList

sqlalchemy_utils.functions

sort_query

escape_like

non_indexed_foreign_keys

is_indexed_foreign_key

identity

is_auto_assigned_date_column

declarative_base

License