Hi Richard,
Thank you for clarification.
And yes, you are right with the guess, that the customer wants to
preserve that much digits ;)
br,
Mathias

2011/8/2 Richard Hipp <d...@sqlite.org>:
> On Tue, Aug 2, 2011 at 12:18 PM, Mathias Legerer
> <mathias.lege...@gmail.com>wrote:
>
>> Hi,
>> I noticed a strange behaviour, when i have a table with a text-field
>> and i put a big float-number into it.
>> When stored, it is increased by one.
>>
>
> Floating-point numbers are approximations.  Always.  No exceptions.  SQLite
> promises to preserve 14 significant digits.  You're getting 15.5 significant
> digits.  Count your blessings.
>
> (1) Unless you are doing number theory or cryptography, you don't need that
> many significant digits.  No real quantity can be measured with that much
> accuracy.
>
> (2) If your boss or your customer insists that you preserve more digits (in
> spite of the fact that in any real-world application, anything after about
> the 5th or 6th digit is probably just noise), then use integers.
>
> FWIW, Linux preserves all 16 digits.  I suppose the difference is how winXP
> sets up the on-chip floating point hardware.
>
>
>>
>> create table TEST (ordnr int primary key, ktoid TEXT);
>> insert into TEST (ordnr, ktoid) values(0, 991000004499464.0);
>> SELECT ordnr, ktoid FROM TEST;
>> 0|991000004499465.0
>>
>> I believe, this is just because of some conversion-library.
>> Documenation says: "If numerical data is inserted into a column with
>> TEXT affinity it is converted into text form before being stored"
>>
>>  I thought that this would work without any problems, but it seems
>> there is some limit for floats/real as text if you look at this bigger
>> number:
>> insert into TEST (ordnr, ktoid) values(3, 99100000449946222.0);
>> -> 3|9.91000004499462e+16
>>
>> Is there some documentation about this limit?
>> Is it system-dependend?
>> I am working on WinXP 32Bit.
>>
>> Thank you for any information.
>> _______________________________________________
>> sqlite-users mailing list
>> sqlite-users@sqlite.org
>> http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
>>
>
>
>
> --
> D. Richard Hipp
> d...@sqlite.org
> _______________________________________________
> sqlite-users mailing list
> sqlite-users@sqlite.org
> http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
>
_______________________________________________
sqlite-users mailing list
sqlite-users@sqlite.org
http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users

Reply via email to