Re: Smallmoney and money rounded to 2 decimals?

2018-04-12 9:37 GMT+01:00 Sebastien FLAESCH <[email protected]>:
> On 04/12/2018 09:41 AM, Frediano Ziglio wrote:
>>
>> 2018-04-06 12:59 GMT+01:00 Sebastien FLAESCH <[email protected]>:
>>>
>>> Hi all,
>>>
>>> Using FreeTDS 1.00.9:
>>>
>>> When fetching a smallmoney or money data, SQLDescribeCol() returns
>>> the sqltype SQL_DECIMAL, precision 10 for smallmoney and or 19 for
>>> money and a scale of 4 for both types, which is fine, since smallmoney
>>> and money can store 4 decimal digits.
>>>
>>> Using an SQL_C_CHAR buffer to hold the values, we see that the decimal
>>> part is rounded to 2 digits...
>>>
>>> Is this expected?
>>>
>>> using other ODBC drivers for SQL Server we get 4 decimal digits.
>>>
>>> Is there some configuration settings to control this?
>>>
>>> Thanks!
>>> Seb
>>
>>
>> Just checked. Yes, apparently Microsoft ODBC drivers format money with
>> 4 decimal digit.
>> I think in the past tools used 2 digits but they moved to 4 along the way.
>> There's actually no way to change that behavior but probably there should
>> be.
>> The 2 digits code is currently quite hard coded in src/tds/convert.c
>> and src/tds/numeric.c.
>> I suppose a good way would be to add a flag to TDSCONTEXT (which is
>> used during conversion to pass locale information).
>>
>> Frediano
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>>
>
> Hello Frediano, and thanks for considering this!
>
> I am not familiar with FreeTDS code internals and TDSCONTEXT.
>
> I you want to keep backward compatibility, I assume that there will be a new
> ODBC connection attribute to control that.
>
> http://www.freetds.org/userguide/odbcconnattr.htm
>
> And if we consider the current behavior as a bug, the default should be 4
> decimal
> digits, and people expecting 2 will have to define the parameter.
>
> MoneyFormatDecDigits=2
>
> You may also consider rounding issues:
> Currently FreeTDS rounds to 2 digits...
> What happens with a db value like 0.1160 ?
> To be fetched as 0.12, or as 0.11 ?
> When 0.11, is this data loss or ok?
> It's monetary data!
>
> I vote for a bug => return always 4 digits.
>
>
> Seb

Got some patches in both Branch-1_00 and master.
On master ODBC uses always 4 digits. I'm considering if this should be
backported too.
Maybe I should just use 4 digits by default, I don't see much
breakage, also considering
Fredy comment on BCP exporting/importing MONEY with bcp surrently is loosing
precision, which is not something we want.

Frediano