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Wolfgang - several of use here are looking into this (trying to decide whether we still need a separate XLink schema, etc.) but using a different namespace is not an option. There's some history here, not all of which is necessary to describe, but to summarize: we originally DID use a homemade namespace, and found that stylesheets would not function properly, and further, that using a namespace other than the W3C XLink namespace for an XLink schema violates the XLink standard. --Ray > -----Original Message----- > From: Metadata Object Description Schema List > [mailto:[log in to unmask]] On Behalf Of Wolfgang Koller > Sent: Monday, March 21, 2011 10:48 AM > To: [log in to unmask] > Subject: Re: [MODS] Problems with Import(s) > > Dear Ray, > > thanks a lot for the explanation. These are all good reasons for you > doing so, however that still doesn't solve the problem that mods is > simply incompatible with other schemas which import from the original > location if a more or less strict validator/parser is used. > > Have you ever thought about adjusting the namespace so that it actually > uses a custom one? (you can argue if that is correct since it is just a > second workaround, but in your case it would greatly improve the > interoperability with other schemas). > If xlink is a custom version, I think it would be even more correct to > use a different name space there. > > After all importing different schemas into the same namespace is often > not supported because for many parsers the same namespace means the > same schema location (AFAIK the behavior for different schemas imported > into the same namespace is undefined by the standard). If the parser is > graceful and tries to parse both schema locations it will result in > errors complaining about re-defined elements (because your schema is > not an addition but a copy). > > Best wishes, > Wolfgang > > > Ray Denenberg, Library of Congress schrieb: > > The xml.xsd question is more easily answered. Several years ago we > > were forced to find a way to reduce the number of MODS accesses to > the > > W3C server. The reason was that W3C was complaining (loudly) about > > excessive accesses and threatening to block certain clients. Someone > > was not properly caching xml.xsd and was in addition validating an > > inordinate number of MODS records. This happened a number of times, > > we were unsuccessful at tracking down the culprit, and as a quick fix > > changed the reference to LC rather than W3C, and the problem has not > resurfaced. > > > > Xlink is more complicated, although you could use the same > > justification, even if there weren't additional complications. In the > > Xlink case, the W3C version simply didn't meet MODS requirements. I > > can't recall exactly why, I'm tracking that down, and I'll get back > to > > you (but I wanted to respond quickly to the question). > > > > --Ray > > > >> -----Original Message----- > >> From: Metadata Object Description Schema List > >> [mailto:[log in to unmask]] On Behalf Of Wolfgang Koller > >> Sent: Monday, March 21, 2011 4:53 AM > >> To: [log in to unmask] > >> Subject: [MODS] Problems with Import(s) > >> > >> Dear all, > >> > >> I'm currently working on a schema which uses MODS to track the > >> bibliographic information of an element. > >> However, unfortunately, there are several critical imports in MODS > >> which heavily conflict with other schema which try to import into > the > >> same namespace (multiple definitions of the same attributes / > elements). > >> > >> Unfortunately MODS uses its own copy of the xml.xsd schema and the > >> xlink.xsd schema. > >> > >> - As far as I found out, the xlink schema is a separate & modified > >> version of the original xlink schema which can be found at > >> http://www.w3.org/1999/xlink.xsd. However from my point of view, it > >> is heavily dangerous to customize a schema but import it into the > >> same namespace then. I would recommend defining a own namespace for > >> your custom schemas (even if they are based on an "official" schema). > >> > >> - The same applies for the xml.xsd schema (the official version can > >> be found at http://www.w3.org/2001/xml.xsd). However there I did not > >> find any difference in the official and the version hosted by loc - > >> what's the reason for hosting it own your own? > >> > >> Is there any chance that you are going to update mods and reference > >> the official schemas and/or change the target namespace so that mods > >> can be combined with others schemas trying to import the official > ones? > >> > >> Best wishes, > >> Wolfgang > >> > >> -------------------------------------- > >> Information gemaess UGB Par. 14 Abs. 1 > >> > >> Naturhistorisches Museum > >> 1010 Wien, Burgring 7 > >> Firmenbuchnummer: FN 236724z > >> Firmenbuchgericht: Handelsgericht Wien > >> UID: ATU 38020609 > >> Rechtsform: Wissenschaftliche Anstalt oeffentlichen Rechts des > Bundes > >> -------------------------------------- > > -------------------------------------- > Information gemaess UGB Par. 14 Abs. 1 > > Naturhistorisches Museum > 1010 Wien, Burgring 7 > Firmenbuchnummer: FN 236724z > Firmenbuchgericht: Handelsgericht Wien > UID: ATU 38020609 > Rechtsform: Wissenschaftliche Anstalt > oeffentlichen Rechts des Bundes > --------------------------------------