diff options
Diffstat (limited to 'lib/sqlalchemy/sql')
| -rw-r--r-- | lib/sqlalchemy/sql/sqltypes.py | 52 |
1 files changed, 43 insertions, 9 deletions
diff --git a/lib/sqlalchemy/sql/sqltypes.py b/lib/sqlalchemy/sql/sqltypes.py index 8f22ae81c..7cf5a6dca 100644 --- a/lib/sqlalchemy/sql/sqltypes.py +++ b/lib/sqlalchemy/sql/sqltypes.py @@ -409,6 +409,7 @@ class BigInteger(Integer): __visit_name__ = 'big_integer' + class Numeric(_DateAffinity, TypeEngine): """A type for fixed precision numbers. @@ -453,7 +454,10 @@ class Numeric(_DateAffinity, TypeEngine): __visit_name__ = 'numeric' - def __init__(self, precision=None, scale=None, asdecimal=True): + _default_decimal_return_scale = 10 + + def __init__(self, precision=None, scale=None, + decimal_return_scale=None, asdecimal=True): """ Construct a Numeric. @@ -468,6 +472,18 @@ class Numeric(_DateAffinity, TypeEngine): datatypes - the Numeric type will ensure that return values are one or the other across DBAPIs consistently. + :param decimal_return_scale: Default scale to use when converting + from floats to Python decimals. Floating point values will typically + be much longer due to decimal inaccuracy, and most floating point + database types don't have a notion of "scale", so by default the + float type looks for the first ten decimal places when converting. + Specfiying this value will override that length. Types which + do include an explicit ".scale" value, such as the base :class:`.Numeric` + as well as the MySQL float types, will use the value of ".scale" + as the default for decimal_return_scale, if not otherwise specified. + + .. versionadded:: 0.9.0 + When using the ``Numeric`` type, care should be taken to ensure that the asdecimal setting is apppropriate for the DBAPI in use - when Numeric applies a conversion from Decimal->float or float-> @@ -487,6 +503,10 @@ class Numeric(_DateAffinity, TypeEngine): """ self.precision = precision self.scale = scale + self.decimal_return_scale = decimal_return_scale \ + if decimal_return_scale is not None \ + else self.scale if self.scale is not None \ + else self._default_decimal_return_scale self.asdecimal = asdecimal def get_dbapi_type(self, dbapi): @@ -525,12 +545,10 @@ class Numeric(_DateAffinity, TypeEngine): 'storage.' % (dialect.name, dialect.driver)) # we're a "numeric", DBAPI returns floats, convert. - if self.scale is not None: - return processors.to_decimal_processor_factory( - decimal.Decimal, self.scale) - else: - return processors.to_decimal_processor_factory( - decimal.Decimal) + return processors.to_decimal_processor_factory( + decimal.Decimal, + self.scale if self.scale is not None + else self._default_decimal_return_scale) else: if dialect.supports_native_decimal: return processors.to_float @@ -576,7 +594,8 @@ class Float(Numeric): scale = None - def __init__(self, precision=None, asdecimal=False, **kwargs): + def __init__(self, precision=None, asdecimal=False, + decimal_return_scale=None, **kwargs): """ Construct a Float. @@ -587,6 +606,17 @@ class Float(Numeric): defaults to ``False``. Note that setting this flag to ``True`` results in floating point conversion. + :param decimal_return_scale: Default scale to use when converting + from floats to Python decimals. Floating point values will typically + be much longer due to decimal inaccuracy, and most floating point + database types don't have a notion of "scale", so by default the + float type looks for the first ten decimal places when converting. + Specfiying this value will override that length. Note that the + MySQL float types, which do include "scale", will use "scale" + as the default for decimal_return_scale, if not otherwise specified. + + .. versionadded:: 0.9.0 + :param \**kwargs: deprecated. Additional arguments here are ignored by the default :class:`.Float` type. For database specific floats that support additional arguments, see that dialect's @@ -596,13 +626,17 @@ class Float(Numeric): """ self.precision = precision self.asdecimal = asdecimal + self.decimal_return_scale = decimal_return_scale \ + if decimal_return_scale is not None \ + else self._default_decimal_return_scale if kwargs: util.warn_deprecated("Additional keyword arguments " "passed to Float ignored.") def result_processor(self, dialect, coltype): if self.asdecimal: - return processors.to_decimal_processor_factory(decimal.Decimal) + return processors.to_decimal_processor_factory( + decimal.Decimal, self.decimal_return_scale) else: return None |