Re: [SQLObject] Decimals in sqlite

[Christopher S. <csi...@gm...>]

On Tuesday 01 July 2008 13:56:26 Oleg Broytmann wrote:
>    Or, if 'quantize' is always equal to precision

Since I believe the intent is to enforce consistency between the Python model 
and the persistent storage, that should be the case.

> class Example(sqlobject.SQLObject):
>     value = sqlobject.DecimalCol(size=10, precision=precision,
>         quantize=True)

How about something like this?

class DecimalStringValidator(DecimalValidator):
    def __init__(self, *args, **kw):
        size = kw.pop('size', NoDefault)
        precision = kw.pop('precision', NoDefault)
        assert precision >= 0, \
                "You must give a precision argument as a positive integer"
        self.precision = Decimal(10) ** (-1 * int(precision))
        super(DecimalStringValidator, self).__init__(*args, **kw)

    def to_python(self, value, state):
        value = super(DecimalStringValidator, self).to_python(value, state)
        if isinstance(value, Decimal):
            value = value.quantize(self.precision)
        return value

    def from_python(self, value, state):
        value = super(DecimalStringValidator, self).from_python(value, state)
        if isinstance(value, Decimal):
            value = value.quantize(self.precision)
        return value

class SODecimalStringCol(SOStringCol):
    def __init__(self, **kw):
        self.size = kw.pop('size', NoDefault)
        assert self.size >= 0, \
               "You must give a size argument as a positive integer"
        self.precision = kw.pop('precision', NoDefault)
        assert self.precision >= 0, \
               "You must give a precision argument as a positive integer"
        kw['length'] = int(self.size) + int(self.precision)
        self.quantize = kw.pop('quantize', False)
        assert isinstance(self.quantize, bool), \
                "quantize argument must be Boolean True/False"
        super(SODecimalStringCol, self).__init__(**kw)

    def createValidators(self):
        validators = super(SODecimalStringCol, self).createValidators()
        if self.quantize:
            validators.insert(0, 
DecimalStringValidator(precision=self.precision))

class DecimalStringCol(StringCol):
    baseClass = SODecimalStringCol