On 12/05/11 10:30 +0200, Nicolas Évrard wrote: > * Cédric Krier [2011-05-12 10:13 +0200]: > >On 12/05/11 09:45 +0200, Paul J Stevens wrote: > >>This makes me wonder if perhaps the whole required state machinery needs > >>to be able to allow zero values on numeric fields to satisfy the > >>requirement. I'm well aware of where this comes from: in python numeric > >>values of zero evaluate to False. However, is a business context an > >>explicit zero-amount is *not* the same as an unspecified amount, or in > >>other words: 0 is not False, only False is False. > > > >Have you ideas about how we could be sure to not have zero-amount per error? > > You can have a sql constraint and a boolean field.
Having a checkbox if checked it allow zero amount as unit price. Like that the user should explicitly says that he want a zero amount price. -- Cédric Krier B2CK SPRL Rue de Rotterdam, 4 4000 Liège Belgium Tel: +32 472 54 46 59 Email/Jabber: [email protected] Website: http://www.b2ck.com/
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