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
