RE: Looking for advice on empty tag usage

I have in the past used an extra control attribute, such as
action="create|update|delete" to indicate what the recipient is expected to
do with the data. You could put this in a separate namespace to minimize the
impact on the schema describing the data itself.
 
Michael Kay


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From: xmlschema-dev-request@w3.org [mailto:xmlschema-dev-request@w3.org] On
Behalf Of Wilde Rebecca L SSgt HQ SSG/STS
Sent: 26 July 2004 17:06
To: xmlschema-dev@w3.org
Subject: Looking for advice on empty tag usage



Hello, 

I'm working on creating an XML schema to be used with XSLT and Web Services
that interfaces with a legacy system.  On this legacy system there are
fields that accept values like "*" to signify that the user wants to clear
whatever was stored in that field before.   I would like to create something
more user friendly and intuitive (while still allowing a user to send an
asterisk to mean clear as well) and so some ideas I have come up with are:

1) Use an empty tag such as <ClearNarrative/> and then putting a group
choice of <ClearNarrative/> and <Narrative/> within my sequenced type.

2) Use an attribute to signify that the field should be cleared on the
legacy system.  Only problem is I don't see a way to use the attribute with
just listing the attribute without a value (i.e. <Narrative clear> instead
of <Narrative clear="Y">.

I cannot just assume that if <Narrative/> is sent to my Web Service that the
user wants the field cleared as some programs that interface may decide to
send all tags whether information is being passed or not.

I was wondering if there might be a best practice around on how best to
solve my problem.  Or if anyone might have some wisdom to share on this type
of situation.

Thank you in advance, 
Rebecca Wilde