Thank you Nicolas for your answer. I understand that an int64 certainly gives me enough precision in the general case. Now what am I supposed to do if the user decides to add a virtual 4 decimal digits number to another number which has only 2 decimal digits? I should first identify this and then multiply by 100 the second number in order to be able to use sqlite built-in operators and functions... Not so simple, I think... And in my case, it is the user who determines the precision he desires for each number within the application, so I cannot have the precision fixed once for all like you suggest. Aladdin
> Date: Sun, 13 Apr 2008 13:41:46 -0500 > From: [EMAIL PROTECTED] > To: sqlite-users@sqlite.org > Subject: Re: [sqlite] Dealing with monetary huge values in sqlite > > On Sun, Apr 13, 2008 at 07:37:33PM +0200, Aladdin Lampé wrote: >> In my opinion (please tell me if I'm wrong), your method only works if >> you want to *display* the values in your column, and if the decimal >> precision doesn't change form line to line. >> >> I would like to be able to perform operations (+, /, %, etc.) and to >> store intermediary results into other columns (such as x% of the >> value, etc.), which may have an arbitrary precision, and - only at the >> end - round the result to cents/pennies etc. This is required into the >> technical specifications provided by my client, because high precision >> matters for them. Indeed, an error of 0.01$ on 10,000,000 lines would >> lead to a significant error at the end... > > The proposed method allows you do perform arithmetic operations using > SQLite's built-in operators and functions. > > If the greatest error your customer is willing to accept is, say, one > part in a million (that is, a millionth of a cent), then using 64-bit > would allow you to represent values up to ~ 10e13 -- 10 trillion, not so > much, but perhaps good enough for you. > > If the tolerance is more like one in 10,000 ($0.0000001), then you can > represent up to ~ 1,000 trillion as the largest value. That's still > pretty small, IMO, but almost certainly good enough for you. > > You can adjust where you put the virtual fixed point. If you can't find > a suitable break then you should consider your arbitrary precision > extended function function scheme (or a database engine that provides > the features you need). > > Nico > -- > _______________________________________________ > sqlite-users mailing list > sqlite-users@sqlite.org > http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users _________________________________________________________________ Créez votre disque dur virtuel Windows Live SkyDrive, 5Go de stockage gratuit ! http://www.windowslive.fr/skydrive/ _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
