Thanks Massimo and everybody else all the alternatives. I've been carefully thinking on it and IMO storing in the database as "float" is the best alternative:
PROS - No conversion is needed to display the amount (just formatting) - You can't make the sql engine to compute a sum() or any oher aggregate operation as a query. - You know that what is in your db is ALMOST what you meant. CONS - You must take care of formatting - If you make use of very big and very small numbers and have A LOT of records. This is not very likely to happen in most cases. I'll do it that way. On 22 mar, 23:03, mdipierro <[email protected]> wrote: > Another possibility: > Make the field 'string' and try this > > class IS_DECIMAL: > def __init__(self,decimals=2,error_message="Invalid"): > self.decimals=decimals > self.error_message=error_message > def __call__(self,value): > import re > if re.compile('\d+(\.\d{1,%s})?'%self.decimals).match(value): > return (value,None) > else: > return (value,self.error_message) > > On Mar 22, 12:19 pm, Paco <[email protected]> wrote: > > > All right, I knew about the implieddecimalpoint solution but it won > > allow you to handle very big numbers. > > > I made a quick check and only SQLite doesn't supportDECIMALtypes. > > > Maybe is worth the effort to make DAL support, for the sake of > > simplicity, a MONEY type and make DAL to 'internaly' supportdecimal > > types in SQLite with implieddecimalpoint. > > > On 21 mar, 03:45, mdipierro <[email protected]> wrote: > > > > try this: > > > > class IS_DECIMAL: > > > def __init__(self,decimals=2,error_message="Invalid"): > > > self.decimals=decimals > > > self.error_message=error_message > > > def __call__(self,value): > > > try: > > > value=int(float(value)*(10**self.decimals)) > > > return (value,None) > > > except: > > > return (value,self.error_message) > > > def format(self,value): > > > return float(value)/10**self.decimals > > > > On Mar 20, 7:41 pm, Joe Barnhart <[email protected]> wrote: > > > > > The easiest workaround is to use INTEGER and leave all amounts in > > > > cents, i.e. 123 instead of 1.23. If all math is done with the implied > > > >decimalpoint on integers, you will never have floating-point round- > > > > off errors. Only put in thedecimalpoint when you are ready to > > > > display the value. (Massimo -- Maybe a validator can help here?) > > > > > -- Joe B. > > > > > On Mar 20, 12:03 pm, Paco <[email protected]> wrote: > > > > > > I've been trying web2py for a couple of days and I believe is just > > > > > great. I'm so excited that I'm planning to build my own accounting and > > > > > invoicing application, which is, in the other hand, not so complex in > > > > > my case. > > > > > > I need (and I believe many more people do) aDECIMALfield type or > > > > > maybe a CURRENCY type since there are many applications that need > > > > > fixed precision numbers. > > > > > > It seems to me that is shouldn't be very difficult to do since most > > > > > databases, including SQLite, support NUMERIC orDECIMALtypes. > > > > > > It would be a great newfeature. Are there any plans to do such a > > > > > thing? Or maybe there is a nice workaround to do this in web2py? > > > > > > Cheers, > > > > > Paco --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "web2py Web Framework" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/web2py?hl=en -~----------~----~----~----~------~----~------~--~---
