Bill Walker/Amigos wrote:
> I am curious about a part of the EAD 2002 DTD.
> In the EAD DTD you have two choices on how to link files to the
> encoded finding aid.
> 1) Declare an entity in the document declaration and add an
> entityref attribute to the linking element in the body of the
> document 2) add an href attribute to the linking element in the body
> of the document.
> Is there any advantage of one over the other?
I think it's horses for courses, and very much depends on the nature of
The advantage of the entityref approach is that a finding aid encoder
can assert a link betwen *logical* entities without knowing about how
the system is being implemented. In theory, URLs can be associated with
the entities at runtime by whatever software (web server, XML editor...)
is handling the delivery.
As the 1998 Application Guidelines say, it is a "technically elegant"
approach, that leaves the assignment of physical locations to separate
catalogue files or other resource brokers. However, as they also say,
> There are technical disadvantages to this approach. Web browsers that
> support XML and the use of XSL or CSS stylesheets are unable to
> access and resolve such entity names into explicit resource addresses
> such as URLs. It would require specialized programming to create
> workarounds for this problem. In addition, the overhead of supplying
> a well-formed FPI (as specified by the ISO 9070 standard) for each
> digital resource is not insignificant.
On our NDAD system (http://ndad.ulcc.ac.uk/), we have stuck with href
for the time being, since our internal references double as URLs (within
our domain) - and everything is transformed into HTML anyway. If the
tide were to change, it doesn't seem like it would be terribly difficult
to harvest all the hrefs and substitute entityrefs.
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