Correct way to setup decimal precision in OpenERP
Wrong setting of decimal precision can result in big problem for accounting. Here is some tips from my experience.
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It is ok (and sometime required to make a valid result) to increase the precision for non-Account items. I.e., Price, Discount.
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But we should not change the precision of Account as it will affect account posting. Also, 2 digit is what we want for our Forms, it should be the same as what is recorded in system.
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In coding, OpenERP is using the same concept as Excel’s “Calculate as Display”. Meaning, each number should be rounded (2 digit as setup in currency) before further calculation.
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Make sure when writing the code, use this concept to avoid future problem.
def cur_round(value):
"""Round value according to currency."""
return cur_obj.round(cr, uid, cur, value)
# add discount
amount_untaxed = sum(line.price_subtotal
for line in getattr(record, self._line_column))
add_disc = record.add_disc
add_disc_amt = cur_round(amount_untaxed * add_disc / 100)
o_res['add_disc_amt'] = add_disc_amt
o_res['amount_net'] = o_res['amount_untaxed'] - add_disc_amt
# we apply a discount on the tax as well.
# We might have rounding issue
o_res['amount_tax'] = cur_round(
o_res['amount_tax'] * (100.0 - (add_disc or 0.0))/100.0)
o_res['amount_total'] = o_res['amount_net'] + o_res['amount_tax']
Note:
You can note from the code that, we always round it (to 2 digits) before pass it to next calculation.
