Re: [Koha] Question on Z39.50 cross-format queries
Sorry, seem to have replied by mistake to the poster and not to the list.
________________________________ From: Manos Petridis <egpetridis@yahoo.com> To: BWS Johnson <abesottedphoenix@yahoo.com> Sent: Monday, August 13, 2012 3:24 PM Subject: Re: [Koha] Question on Z39.50 cross-format queries
Thank you for your welcome Brooke, and for your prompt reply. I do understand that my own installation can be either USMARC/MARC21 or UNIMARC. What I was enquiring about is Z39.50 look-ups. Why I am puzzled: a) It it were simply a case of either/or, then why can I select the MARC flavour of the various Z39.50 origins set up at my installation? What is the reason to let koha know of the MARC flavour/dialect, if it not able to use the data that each server sends? There must be some functionality behind the dropbox selections, even if it only defines the query statement dialect. b) From What I can see in the data presented (in the MARC form window) it sometimes is just a matter of mapping. For example, it seems that
in SUTRS, information is stored in the following keys: Title: 200 Author: 700_a, 700_b, 701_a, 701_b...Editon details 210 Physical descrition: 215 DDC*: 676_a DDC description: 676_9 Subjects: 606
in USMARC, information is stored in the following keys: Title: 245 Author: 700 Editon details 260 Physical descrition: 300 DDC*: 082 (revision and Category) Subjects: 650, 505 (fixed and free-form) LCCN: 010 in UNIMARC, information is stored in the following keys: Title: 200 Author: 700, 701Editon details 210 Physical descrition: 215 DDC*: 676 (revision and Category)Subjects: 606, 712 (fixed and free-form) This is what I meant when I wrote "I understand that both standards encode the same more-or-less information, differently" in my original message. There are bound to be differences, sure, but I'm looking for the gest in the MARC records, not the details that frankly I don't even know what they represent.
I understand that even the information retrieved via Z39.50 from same-flavour installations, passes some kind of mapping, from the MARC record form to the form of the various tables and fields/columns used by the specific software/implementation, koha in our case. I expect therefore that it would be a matter of utilising the appropriate mapping tables, as dictated by the MARC setting of each Z39.50 origin, so that koha could make use of "foreign" MARC records. kind regards, Manos Petridis--- From: BWS Johnson <abesottedphoenix@yahoo.com> To: "koha@lists.katipo.co.nz" <koha@lists.katipo.co.nz> Sent: Monday, August 13, 2012 1:21 PM Subject: Re: [Koha] Question on Z39.50 cross-format queries
Salvete!
Welcome to the Community. :)
Question: I have selected USMARC/MARC21 as my installation's native format. This serves nicely when I perform Z39.50 queries against many USMARC/MARC21 sources. On the other hand, when I perform Z39.50 queries against UNIMARC sources, I don't get properly formatted results even though I have set-up those sources (origins) as UNIMARC in koha.
I understand that both standards encode the same more-or-less information, differently. Therefore - if I understand correctly - koha would have to request from an UNIMARC-only-capable source that they return UNIMARC-formatted results, and koha would need to map them - if and as possible - to the native format of my installation, i.e. USMARC/MARC21.
Apparently this doesn't happen. Is it normal?
That is very normal. MARC21/UNIMARC is an either or standard selection. You may have MARC21 or you may have UNIMARC. To my knowledge, you may not have both.
That said, when this last came up, I can see the point of wanting to be able to run both in parallel if you absolutely MUST have both. Suggestions for how to do that are here:
http://koha.1045719.n5.nabble.com/Software-error-td5114149.html
Cheers, Brooke
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Op 13-08-12 21:36, Manos Petridis schreef:
a) It it were simply a case of either/or, then why can I select the MARC flavour of the various Z39.50 origins set up at my installation? What is the reason to let koha know of the MARC flavour/dialect, if it not able to use the data that each server sends? There must be some functionality behind the dropbox selections, even if it only defines the query statement dialect.
Koha needs to know what you are using, so that it knows what field to pull from for the title, and how to index the title in zebra to make it correctly searchable, for example. There are a number of other cases where the differences are a bit deeper than just different field IDs.
b) From What I can see in the data presented (in the MARC form window) it sometimes is just a matter of mapping. For example, it seems that
It's not really feasible to correctly map from UNIMARC to MARC21 in an automated fashion. MARC rules extend beyond what field something is in, to what information is made available, and how it is formatted within the field. You could probably get a pretty good automated conversion, but it would almost certainly be lossy. -- Robin Sheat Catalyst IT Ltd. ✆ +64 4 803 2204 GPG: 5957 6D23 8B16 EFAB FEF8 7175 14D3 6485 A99C EB6D
________________________________ From: Robin Sheat <robin@catalyst.net.nz> To: koha@lists.katipo.co.nz Sent: Tuesday, August 14, 2012 1:07 PM Subject: Re: [Koha] Question on Z39.50 cross-format queries
Op 13-08-12 21:36, Manos Petridis schreef:
a) It it were simply a case of either/or, then why can I select the MARC flavour of the various Z39.50 origins set up at my installation? What is the reason to let koha know of the MARC flavour/dialect, if it not able to use the data that each server sends? There must be some functionality behind the dropbox selections, even if it only defines the query statement dialect.
Koha needs to know what you are using, so that it knows what field to pull from for the title, and how to index the title in zebra to make it correctly searchable, for example. There are a number of other cases where the differences are a bit deeper than just different field IDs.
That's exactly my point! Koha knows a) what MARC flavor my installation is using b) what MARC form each Z39.50 origin accepts requests and supplies its results in It should therefore be able to know "what field to pull from for the title" etc. I would expect that zebra indexes the various koha tables, not the imported MARC records, i.e. works on data past the mapping phase.
b) From What I can see in the data presented (in the MARC form window) it sometimes is just a matter of mapping. For example, it seems that
It's not really feasible to correctly map from UNIMARC to MARC21 in an automated fashion. MARC rules extend beyond what field something is in, to what information is made available, and how it is formatted within the field. You could probably get a pretty good automated conversion, but it would almost certainly be lossy.
If I understand things correctly, Z39.50 look-ups are used in koha cataloging as an aid, rather than a gospel to be strictly adhered to. This is evident both in the differences between MARC records from different reputable origins - apparently all manned by skilled librarians - and by the nature of some of the information provided in query results: why do I care for example where a specific item is stored in library X, when I'm only interested to document my own copy in my own library? Lossy conversion can be a boon in this context. As long as standards are well defined, one can perform formatting conversions correctly (character to numerical, left/right justified, etc.), partially at least, i.e. for specific common fields. Alas, I'm perl-impaired so I'm in no position to substantiate this view.
-- Robin Sheat Catalyst IT Ltd. ✆ +64 4 803 2204 GPG: 5957 6D23 8B16 EFAB FEF8 7175 14D3 6485 A99C EB6D _______________________________________________ Koha mailing list http://koha-community.org/ Koha@lists.katipo.co.nz http://lists.katipo.co.nz/mailman/listinfo/koha
* Manos Petridis (egpetridis@yahoo.com) wrote:
________________________________ From: Robin Sheat <robin@catalyst.net.nz> To: koha@lists.katipo.co.nz Sent: Tuesday, August 14, 2012 1:07 PM Subject: Re: [Koha] Question on Z39.50 cross-format queries
Op 13-08-12 21:36, Manos Petridis schreef:
a) It it were simply a case of either/or, then why can I select the MARC flavour of the various Z39.50 origins set up at my installation? What is the reason to let koha know of the MARC flavour/dialect, if it not able to use the data that each server sends? There must be some functionality behind the dropbox selections, even if it only defines the query statement dialect.
Koha needs to know what you are using, so that it knows what field to pull from for the title, and how to index the title in zebra to make it correctly searchable, for example. There are a number of other cases where the differences are a bit deeper than just different field IDs.
That's exactly my point! Koha knows a) what MARC flavor my installation is using b) what MARC form each Z39.50 origin accepts requests and supplies its results in It should therefore be able to know "what field to pull from for the title" etc. I would expect that zebra indexes the various koha tables, not the imported MARC records, i.e. works on data past the mapping phase.
Then you would be expecting wrong, it indexes the MARC, which is stored as marcxml in the biblioitems table. If yuo want more in depth on the internals of Koha, it's better on the koha-devel list. Only a small fraction of the over 900 marc fields (most of which are repeatable) and their myriad of subfields (also repeatable) are mapped to columns in the database and stored. The cataloguers on this list will be able to tell you much better than I, but a crosswalk between UNIMARC and MARC21 (or NORMARC, or DANMARC or whatever else) is very hard to pull off, when you have to deal with control fields, indicators etc Chris -- Chris Cormack Catalyst IT Ltd. +64 4 803 2238 PO Box 11-053, Manners St, Wellington 6142, New Zealand
Op 14-08-12 12:50, Manos Petridis schreef:
That's exactly my point! Koha knows a) what MARC flavor my installation is using b) what MARC form each Z39.50 origin accepts requests and supplies its results in It should therefore be able to know "what field to pull from for the title" etc.
It is technically feasible to have a catalogue that is a mix of UNIMARC and MARC21, however no one has done this, probably because libraries don't work that way in general.
I would expect that zebra indexes the various koha tables, not the imported MARC records, i.e. works on data past the mapping phase.
I wouldn't expect that, but I'm biased because I know how it works :) (to some degree, anyway.)
If I understand things correctly, Z39.50 look-ups are used in koha cataloging as an aid, rather than a gospel to be strictly adhered to.
It depends on the library. Some take it and don't look at it much, some may spend a lot of time tweaking it.
This is evident both in the differences between MARC records from different reputable origins - apparently all manned by skilled librarians - and by the nature of some of the information provided in query results: why do I care for example where a specific item is stored in library X,
Items aren't stored in the MARC you get from Z39.50.
when I'm only interested to document my own copy in my own library? Lossy conversion can be a boon in this context.
It really boils down to that no one has done this because no one who needs it has sponsored the development :) It wouldn't be a trivial bit of work.
As long as standards are well defined,
Yeah, you'd think that. MARC isn't terribly well defined, it's also quite terrible in general (e.g. mixing syntax and semantics at the same level, and other such crimes.) -- Robin Sheat Catalyst IT Ltd. ✆ +64 4 803 2204 GPG: 5957 6D23 8B16 EFAB FEF8 7175 14D3 6485 A99C EB6D
participants (3)
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Chris Cormack -
Manos Petridis -
Robin Sheat