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  • From: Sebastien FLAESCH <sf AT 4js.com>
  • To: freetds AT lists.ibiblio.org
  • Subject: Re: [freetds] Smallmoney and money rounded to 2 decimals?
  • Date: Mon, 16 Apr 2018 11:45:40 +0200

On 04/16/2018 11:39 AM, Frediano Ziglio wrote:
2018-04-12 9:37 GMT+01:00 Sebastien FLAESCH <sf AT 4js.com>:
On 04/12/2018 09:41 AM, Frediano Ziglio wrote:

2018-04-06 12:59 GMT+01:00 Sebastien FLAESCH <sf AT 4js.com>:

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
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Hi Frediano!

Sounds good... thanks a lot.

Seb




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