Hi Michael
Message: 1
Date: Tue, 04 Jul 2006 09:42:06 +0100
From: Michael Hawksworth <[EMAIL PROTECTED]>
Subject: Re: field storage on an object
To: [EMAIL PROTECTED]
Message-ID: <[EMAIL PROTECTED]>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
As it requires your form to 'know' what the data structure is you
degrade the abstraction.... but between you and me, I do it for
maintenance forms as I can then automate most functions. I doubt many
would care about the abstraction at the form level saying that the
business object is presenting a field object for you to use in the
format you want which is sophistry but in a sense true.
You will add a lot more work if you add more 'field' objects to your
business object (say an address object) as you then need to look at
recombining these back to your business objects real representation of
the data (which in turn is abstracted from x number of data-objects!
urg). While it isn't that hard you can make a rod for your back in
complex bo's. That said once you have it right the UI components are
completely divorced from the actual data as effectively you bo has to
undertake the transfer. This also allows you to use validation on
smaller components specific to the 'field' grouping and not using a
standard validation component on the whole record.
Might I suggest a slight variation? An invoice demonstrates a need to
deal with sets of records - the line items. There may even be several
parent records each with their own children that have to be committed.
The BO might interact with an object that can either handle
hierarchichal data on its own, or with a set of data objects that can
be arranged into a hierarchy.
A design for a BO which holds a single record may prove limiting -
until a workaround is implmented to iterate through the line items,
scatter to the BO and commit.
Mike
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