From fcf539d090a95fb179ca03beffd10122e97aa002 Mon Sep 17 00:00:00 2001 From: Mike Bayer Date: Mon, 22 Feb 2021 09:55:21 -0500 Subject: [PATCH] document TypeDecorator schemes for MONEY this type apparently returns strings so document cast/processing options. Change-Id: Idc19527dcf76e1c2d966425716c0fcf60cbba5dc References: #5965 --- lib/sqlalchemy/dialects/postgresql/base.py | 36 +++++++++++++++++++++- 1 file changed, 35 insertions(+), 1 deletion(-) diff --git a/lib/sqlalchemy/dialects/postgresql/base.py b/lib/sqlalchemy/dialects/postgresql/base.py index 3362655528..d34d8dd17b 100644 --- a/lib/sqlalchemy/dialects/postgresql/base.py +++ b/lib/sqlalchemy/dialects/postgresql/base.py @@ -1539,7 +1539,41 @@ PGMacAddr = MACADDR class MONEY(sqltypes.TypeEngine): - """Provide the PostgreSQL MONEY type. + r"""Provide the PostgreSQL MONEY type. + + Depending on driver, result rows using this type may return a + string value which includes currency symbols. + + For this reason, it may be preferable to provide conversion to a + numerically-based currency datatype using :class:`_types.TypeDecorator`:: + + import re + import decimal + from sqlalchemy import TypeDecorator + + class NumericMoney(TypeDecorator): + impl = MONEY + + def process_result_value(self, value: Any, dialect: Any) -> None: + if value is not None: + # adjust this for the currency and numeric + m = re.match(r"\$([\d.]+)", value) + if m: + value = decimal.Decimal(m.group(1)) + return value + + Alternatively, the conversion may be applied as a CAST using + the :meth:`_types.TypeDecorator.column_expression` method as follows:: + + import decimal + from sqlalchemy import cast + from sqlalchemy import TypeDecorator + + class NumericMoney(TypeDecorator): + impl = MONEY + + def column_expression(self, column: Any): + return cast(column, Numeric()) .. versionadded:: 1.2 -- 2.47.2