Because it's an inconsistant dependency which makes it nonnormalized. Sure that's database design theory and rules can be broken if there's enough benefit.
But consider the real world dificulties that arise when you have incosistant dependency. If you're entire application world is OFBiz, there is no problem. But, if you have an outside application pulling information from the OFBiz database, it now has to go through OFBiz's entity engine to get it or it has to be aware that some of the credit card information is in the PaymentMethod entity. This is unnecessary if you keep the data model normalized whenever possible. It is certainly possible in this instance. --- "David E. Jones" <[EMAIL PROTECTED]> wrote: > > If each type of PaymentMethod might have a > description on it (ie CreditCard, EftAccount, etc), > then why not put if on the PaymentMethod entity? In > fact, I think it's somewhat silly not to... > > -David > > > Chris Howe wrote: > > Re first comment: > > > > If a paymentMethod requires no additional entity > what > > is the name doing for you that the type isn't? > > > > Re second comment (but there is no description > on...): > > > > I'm saying that there should be a > > CreditCard.description, et al but not a > > PaymentMethod.description. > > > > Re third comment (if i have to .getRelated it's a > > mess): > > > > And if i'm only working with credit cards, I have > to > > .getRelated back to the PaymentMethod. Isn't that > the > > same mess? There's no benefit except for this > > specific application. You're sacrificing > > normalization in the data model for coding ease > that > > doesn't run both ways. > > > > Placing the description in the PaymentMethod for > what > > you're wanting to accomplish creates an > inconsistant > > dependency. > > > > > > --- Si Chen <[EMAIL PROTECTED]> > wrote: > > > >> On Jun 28, 2006, at 4:21 PM, Chris Howe wrote: > >> > >>> Let me explain it differently. The > PaymentMethod > >>> entity is an entity of convenience, not an > entity > >> that > >>> describes anything. > >> No, it's an entity that describes a payment > method. > >> There are some > >> payment methods which have additional information > >> specific to them, > >> but then again there may be some other payment > >> methods which don't > >> require additional entities. > >>> So now we add description. But, there's already > a > >>> description (firstName, lastName) for Person and > a > >>> description (groupName) for Corporation. This > is > >>> information that is likely to change and we will > >> need > >>> to keep track of it in multiple locations when > it > >> is > >>> unneccesary. > >>> > >> But there is no description on CreditCard, > >> EftAccount, nor is there > >> an equivalent field. So this is not the case > right? > >>> So, there's no benefit of adding the > description, > >> but > >>> you've added the possibility of the > nonnormalized > >> data > >>> to be inconsistant. Does that make a good data > >> model? > >> > >> Actually there's a real benefit. If I just want > to > >> get the > >> description of a PaymentMethod and it's on the > >> PaymentMethod, it's > >> very easy. If I have to .getRelated based on the > >> type of the > >> PaymentMethod to another entity, it's a mess. > >> > >>> > >>> > >>> --- David E Jones <[EMAIL PROTECTED]> wrote: > >>> > >>>> Huh? > >>>> > >>>> Chris Howe wrote: > >>>>> It may apply to all payment methods (I'm not > >>>> really > >>>>> sure that it applies to all current payment > >>>> methods, > >>>>> much less ALL that may exist), but it does not > >>>>> describe the payment method. It describes the > >>>> payment > >>>>> method's child so it should go in the entity > >> that > >>>> it > >>>>> is describing. > >>>>> > >>>>> Following through with the approach of putting > >> the > >>>>> field in PaymentMethod entity puts you in the > >>>> position > >>>>> of modifying the data to fit the data model > >>>> instead of > >>>>> keeping the data model flexible enough to fit > >> the > >>>>> data. > >>>>> > >>>>> --- Si Chen <[EMAIL PROTECTED]> > >>>> wrote: > >>>>>> I disagree. This is a descriptive note that > >>>> applies > >>>>>> to all > >>>>>> PaymentMethods so why put it in the child > >>>> entities. > >>>>>> If you had a > >>>>>> parent class which had a field that all > >> inherited > >>>>>> classes should > >>>>>> have, shouldn't be in the parent class? > >>>>>> > >>>>>> > >>>>>> > >>>>>> On Jun 28, 2006, at 1:35 PM, Chris Howe > wrote: > >>>>>> > >>>>>>> "Bank A general account" does not describe > the > >>>>>>> PaymentMethod, it describes the credit card, > >> the > >>>>>>> company account, the gift card, etc so that > >>>> field > >>>>>>> should go on the CreditCard, etc entity. > Now > >> if > >>>>>>> you're using it as an alias for the Payment > >>>>>> Method, > >>>>>>> then you should create a > >> PaymentMethodAttribute > >>>>>> entity > >>>>>>> and make a relationship between the two. > >>>>>>> > >>>>>>> > >>>>>>> On a side note. I've noticed a couple of > >> fields > >>>>>>> getting added onto entities in svn that are > >>>> quick > >>>>>>> fixes to gain functionality but cause a loss > >> of > >>>>>> the > >>>>>>> entity's meaning. PaymentMethod.partyId is > >> one > >>>>>> that > >>>>>>> quickly comes to mind. > >>>>>>> > >>>>>>> --- Si Chen > <[EMAIL PROTECTED]> > >>>>>> wrote: > >>>>>>>> Hi everybody. > >>>>>>>> > >>>>>>>> What do you think of adding a field > >>>>>>>> "paymentMethodName" to > >>>>>>>> PaymentMethod, so a company can identify > that > >>>>>> method > >>>>>>>> A is "Bank A > >>>>>>>> general account", etc. etc. > >>>>>>>> > >>>>>>>> Si > >>>>>>>> > >> > > >
