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

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__ = 'document'
    id = sa.Column(sa.Integer, autoincrement=True)
    name = sa.Column(sa.Unicode(50))
    background_color = sa.Column(ColorType)


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