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how to assign tag numbers |
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|
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|
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* standards |
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|
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> IIF |
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(ISO 2709) makes a distinction between |
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- control fields 001-009 |
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which must be the leading fields in a record in order of increasing tags. |
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Control fields do not use any subfields, i.e. no indicators nor subfield |
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delimiters or identifiers. |
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IIF demands exactly one field 001, which must hold a record control number. |
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002 is reserved for subrecord purposes, others are implementation defined. |
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(IIF also supports alpha tags 00a-00z, which are not supported by ISIS |
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and to my knowledge not used in bibliographical standards). |
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- data fields with arbitrary tags |
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to be in any ordering, but after all control fields. |
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All data fields start with a fixed number of indicators (two in MARC) |
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followed by subfields, each introduced by a delimiter and identifier. |
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|
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Unimarc, Marc21 and even MAB agree on the use of 005 as version identifier, |
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holding a last modified time as YYYYMMDDHHMMSS.T (with tenths of a second) |
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according to ISO 8601. |
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Marc21 additionally uses 003 as "control number identifier" |
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(identifying the organization who assigned 001), |
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006 for "additional material characteristics", |
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007 for physical description and 008 for "general information" |
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like date and place of publication. |
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|
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Other 0xx tags are typically used for various other identifiers and |
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classifications of the record like an ISBN, a number according to some |
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national bibliography, dewey decimal classification and so on. |
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|
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|
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* recommendations |
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|
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It is suggested to use (00)1 and (00)5 as record "control number" |
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(unique primary key) and last modified time. |
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Probably it is also not such a bad idea of IIF to reserve (00)2 |
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for "subrecord purposes". |
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|
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|
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If you are storing bibliographical or similar data, or the number of fields is |
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in the hundreds for some other reason, it is suggested to assign tags in nice |
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blocks of 100 like |
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> http://www.ifla.org/VI/3/p1996-1/sec-uni.htm Unimarc |
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does, using 0xx for identifiers. |
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|
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Typically you will want to stick to IIF's restrictions on control fields |
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vs. data fields only if you are actually using some MARC format. |
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Yet, some future special support for a primary key in field 001 might |
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require it to be the first field. |
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|
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|
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In other typical database applications like storing addressbook data, |
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email headers or shop orders, use (0)10 - (0)99, possibly arranged in |
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blocks of 10 (e.g. personal, postal, phone and so on). |
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|
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|
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Use 3,4 and 6-9 for what you somehow consider "control fields" or to save |
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some digits if you really are going to get by with 6 "data fields". |
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|
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|
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Use 0 for unqualified text. |
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Do not use negative tags other than for counted subrecords. |
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|
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$Id: TagUse.txt,v 1.2 2004/07/26 13:20:18 kripke Exp $ |