Example showing how SQLAlchemy blends a property into a synonym

synonym_with_setter.py

# encoding: utf-8

"""
Configuration of a `synonym` property via the mapper function actually
detects an existing property on the mapped class and blends this into
the propertyProxy it creates.

This is actually helpful but as of SQLAlchemy 1.3.4 this seems to be an
undocumented feature.
"""

from sqlalchemy import *
from sqlalchemy.orm import *

metadata = MetaData()

names_table = Table(
    "names", metadata,
    Column("id", Integer, primary_key=True),
    Column("name", String),
)

class Name(object):
    def __init__(self, name):
        self.name = name

    @property
    def name(self):
        return self._name

    @name.setter
    def name(self, name):
        self._name = name[:1].upper() + name[1:]


mapper(Name, names_table, column_prefix="_", properties={
    "name": synonym("_name"),
})

engine = create_engine("sqlite:///", echo=True)
metadata.create_all(engine)

session = sessionmaker(engine)()
t = Name("lowercased")
session.add(t)
session.commit()

print(session.query(Name.name).all())