ColumnAlchemy 0.9.2

additional column types for SQLAlchemy

This repo contains a custom column types for SQLAlchemy which I use in different projects.

The code should be compatible with SQLAlchemy 1.2.3 - 1.4.x.

pip install ColumnAlchemy

UTCDateTime

UTCDateTime stores a Python tz-aware datetime.datetime value as UTC datetime in the database (without explicit timezone information). I use this to introduce tz-aware timezones in systems which expect "naive" datetimes in the database.

from schwarz.column_alchemy import UTCDateTime

class Foo(Base)
    __tablename__ = 'foo'
    id = Column(Integer, autoincrement=True, primary_key=True)
    timestamp = Column(UTCDateTime)

ShiftedDecimal

ShiftedDecimal stores a Decimal as integer in the database (with limited precision). This is especially useful to store decimal values even in sqlite which requires special treatment to store decimals.

from decimal import Decimal
from schwarz.column_alchemy import ShiftedDecimal

class Foo(Base)
    __tablename__ = 'foo'
    id = Column(Integer, autoincrement=True, primary_key=True)
    percentage = Column(ShiftedDecimal(4))

foo = Foo(percentage=Decimal('1.2324'))
# stores percentage as 12324 in the database but returns the
# correct Decimal value after loading.

ValuesEnum

TODO

IntValuesEnum

TODO

YearMonthColumn

YearMonth is similar to datetime.date but without a day attribute. It can be used to represent a calendar month and provides some convenience methods like first_date_of_month() and last_date_of_month(). A YearMonthColumn stores a YearMonth instance as "YYYY-MM" in the database.

from schwarz.column_alchemy import YearMonth, YearMonthColumn

class Foo(Base)
    __tablename__ = 'foo'
    id = Column(Integer, autoincrement=True, primary_key=True)
    month = Column(YearMonthColumn())

foo = Foo(month=YearMonth(2020, 7))
# stores "month" as "2020-07" in the database but returns a
# YearMonth instance after loading.

YearMonthIntColumn

Very similar to YearMonthColumn but stores YearMonth(2020, 7) as 202007 (integer).