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

.. SQLAlchemy-Utils documentation master file, created by
   sphinx-quickstart on Tue Feb 19 11:16:09 2013.
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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
-----------------

.. module:: sqlalchemy_utils

.. autoclass:: InstrumentedList
    :members:


.. module:: sqlalchemy_utils.functions

.. autofunction:: sort_query
.. autofunction:: escape_like
.. autofunction:: non_indexed_foreign_keys
.. autofunction:: is_indexed_foreign_key
.. autofunction:: identity
.. autofunction:: is_auto_assigned_date_column
.. autofunction:: declarative_base


.. include:: ../CHANGES.rst


License
-------

.. include:: ../LICENSE