Robina:
The reason I generally prefer separate elements (in addition to the ones
you cite) is a very practical one--it's very difficult to enforce standard
separating punctuation. If you have data where punctuation is used
ambiguously, crosswalking, display or any other use of the data becomes
quite problematic. Consider, for instance, what happens if LCSH headings
using commas to enforce the order of words get mixed with commas separating
actual headings. You'd have the same difficulty if your name data included
corporate names with hierarchies separated by commas and then used the same
separator for multiple instances. Lots of other examples, of course.
A lot depends, of course, on how you're acquiring your data and how
reliable the source, but in general, repeats are safer, in my view.
Diane
At 10:23 AM 9/13/2001 +0100, you wrote:
>Hi,
>
>I have been asked for the rationale for repeating a DC element rather than
>putting multiple values in one occurence of an element. This is not
>something I have thought about in terms of stating a general principle and
>cannot find any specific information.
>
>My thoughts are: firstly you would repeat an element if you wanted to enter
>values of different types i.e. qualify the element with a scheme. For
>example - DC.Subject expressed as LCSH and a repeat for DDC. If the value
>of DC.Subject were simply going to be several keywords then repeats would be
>superfluous and all the words could go in one instance of the element.
>
>A second reason for using repeats could be where the values of an element
>need to be clearly differentiated because they refer to entities that are
>different in their own right - e.g. several Creators.
>
>Finally, there may well be implementation specific reasons - for example the
>data structures in a source database that is being used to generate DC may
>lend themsleves to repeats rather than concatenation of values. This could
>also apply in reverse if the DC metadata was being designed with a view to
>conversion to another metadata format.
>
>In terms of general principles that is as far as I have got. I'd be grateful
>for any insights anyone else may have.
>
>Thanks,
>Robina
>
>- - - - - - - - - - - - - - - - - - - - - - -
>Robina Clayphan
>National Bibliographic Service
>The British Library
>
>
>
>
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