eml attribute

[Dan Higgins]

Hi All,

    I just thought I would document a few thoughts about the way 
'attribute' is structured in eml-2.0.0beta9.

    In particular, the beta9 version of the attribute module has an 
element called  "storageType". As I understand it, the preferred use of 
this attribute is to contain the XMLSchema datatype of the attribute 
(e.g. 'string'). The attribute module also has a subtree named 
'attributeDomain' with the three branches 'enumeratedDomain', 
'textDomain', and 'numericDomain'.
    It seems to me that the "storageType" and "attributeDomain" elements 
are logically related, but that relation is not indicated in the 
attribute module. As an example, consider a storageType of 'string'. 
With XMLSchema datatypes, the concept of a datatype is limited using 
"facets". Thus a string can be further restricted using (for example) 
'enumeration', 'maxLength, or 'pattern' constraining facets. Similarly, 
'totalDigits' or other facets can be used to contrain a "decimal" datatype.
    In the 'attribute' module of eml, however, such contraints are put 
into the 'attributeDomain' subtree. The 'enumeratedDomain' subelement 
does have the ability to enter code values and the associated definition 
(a code/definition facet is NOT available in XMLSchema datatypes), but 
the 'enumeratedDomain' subelement does NOT have a simple enumeration 
where one just lists allowed values for an attribute.

    In summary, I would suggest that the enumeratedDomain element should 
have a simple 'enumeration' child with the ability to just list allowed 
values (and not require definitions), and/or we should combine the 
'storageType' and 'attributeDomain' elements into something like the 
structure used with XMLSchema datatypes and contraining 'facets'/

Dan Higgins

attribute tree structure-- 
---------------------------------
Dan Higgins
Software Developer
National Center for Ecological Analysis and Synthesis (NCEAS) 
735 State St. Rm 205 
Santa Barbara, CA 93101 
805-892-2531 
higgins at nceas.ucsb.edu 
---------------------------------

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