02. Special fields and subfields

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Subfield indicators in CBS MARC 21 cataloguing format and CBS MARC PICA format – Universal exceptions

The starting point is that, in principle, the MARC 21 (cataloguing) subfields (Library of Congress and WorldCat) within the fields are the same in the CBS MARC 21 cataloguing format and the CBS MARC 21 PICA+ format (i.e. the database format). However, there are several universal exceptions. The reason for these differences are the demands and features of the software and configuration of a CBS MARC 21 database.

OCLC MARC format	Description	CBS MARC cataloguing format	CBS MARC PICA+ format	Explanation
<Indicator values>	Indicators	<Indicator values>	$S	In the CBS MARC 21 format, the indicator values are put in one subfield $S in PICA+.
$0	Authority record control number or standard number	$0	$0	Subfield $0 can contain a number that is not a PPN¹. Within a CBS, PPN's are very important. That's why a special subfield $Z has been defined in the cataloguing format; and a subfield $9 in the PICA+ format. For the CBS software, it is very important to be able to distinguish PPN's and non-PPN's.
n/a	n/a	$Z	$9
n/a	Expansion		$8	The most important field(s) and subfield(s) in the record to which the PPN ($Z / $9) is linked, are displayed. The PPN is “expanded”, i.e. the most important subfield(s) of the field(s) in the record to which the PPN is linked, are displayed. The “expansion” is generated during display; this data is not stored in the database.
$6	Linkage	$6	$T and $U	In CBS MARC 21, subfield $6 contains both occurrence and script code elements separated by a slash (“/”). PICA+ subfield $T contains the occurrence and PICA+ subfield $U the script code. In the MARC 21 subfield $6 an orientation code may be used. “For a display of the field, the default field orientation is left-to-right. When the field contains text that has a right-to-left orientation, the script identification code is followed by a slash (/) and the field orientation code. The MARC field orientation code for right-to-left scripts is the letter r. The orientation code is only included in fields with right-to-left orientation, since left-to-right orientation is the default orientation in 880 fields.”² In the CBS MARC 21 format, this orientation code is not used. When a tag contains Arabic script for example, the field orientation is per definition right-to-left so, using an orientation code has no additional value.
$8	Field link and sequence number	$8	$X	PICA+ subfield $8 is used in CBS for displaying expansions (see above), so the MARC subfield $8 must be converted to another subfield, in this case subfield $X in PICA+.
$9	Special Entry	$9	$Y	In the OCLC MARC 21 format, subfield $9 is part of several tags and contains user-specific information. However, PICA+ subfield $9 in CBS MARC 21 holds a PPN as a link to another bibliographic or authority record (see above), so again the MARC subfield must be converted to another subfield, which is PICA+ subfield $Y in this case.

1. A PPN is the record control number in CBS. PPN literally means “PICA Production Number”.
2. See: Appendix A - Control Subfields of the Library of Congress MARC 21 documentation.

CBS fields 0900 / 098A, 1900 / 198A, 2900 / 298A and 0901 / 098B, 1901 / 198B, 2901 / 298B – bibliographic format

Next fields are important for the data import and the storage of data in a CBS MARC 21 database, e.g. to prevent data loss.

CBS tag	PICA+ tag	Description
0900	098A	Tag for storing data which are not part of the CBS MARC 21 format and must be kept on the main level (level 0) of the format in the database.
1900	198A	Tag for storing data which are not part of the CBS MARC 21 format and must be kept on the local level (level 1) of the format in the database.
2900	298A	Tag for storing data which are not part of the CBS MARC 21 format and must be kept on the copy level (level 2) of the format in the database.
0901	098B	Tag for holding data on the main level (level 0) of the CBS MARC 21 format which is no longer in use. Or this tag holds data temporarily, i.e. (a selection of) the data in tag 098B is converted to the appropriate CBS (MARC 21) field(s) and subfield(s). When this is ready, tag 098B is deleted in principle.
1901	198B	Tag for holding data on the local level (level 1) of the CBS MARC 21 format which is no longer in use. Or this tag holds data temporarily, i.e. (a selection of) the data in tag 198B is converted to the appropriate CBS (MARC 21) field(s) and subfield(s). When this is ready, tag 198B is deleted in principle.
2901	298B	Tag for holding data on the copy level (level 2) of the CBS MARC 21 format which is no longer in use. Or this tag holds data temporarily, i.e. (a selection of) the data in tag 298B is converted to the appropriate CBS (MARC 21) field(s) and subfield(s). When this is ready, tag 298B is deleted in principle.

CBS fields 0900 / 098A and 0901 / 098B – authority format

Next fields are important for the data import and the storage of data in a CBS MARC 21 database, e.g. to prevent data loss.

CBS tag	PICA+ tag	Description
0900	098A	Tag for storing data which are not part of the CBS MARC 21 format and must be kept on the main level (level 0) of the format in the database.
0901	098B	Tag for holding data on the main level (level 0) of the CBS MARC 21 format which is no longer in use. Or this tag holds data temporarily, i.e. (a selection of) the data in tag 098B is converted to the appropriate CBS (MARC 21) field(s) and subfield(s). When this is ready, tag 098B is deleted in principle.

CBS subfield $@ – bibliographic and authority format

CBS MARC 21 subfield $@ is used when subfields are stored in the CBS MARC 21 database which are not part of the official MARC 21 format of the Library of Congress and the MARC 21 format of OCLC (WorldCat). It can be used for both bibliographic and authority fields in a CBS MARC 21 database.

Subfield $@ is composed of the original subfield code as the first character, followed by a pipe symbol (|), and then the contents of the original subfield.

Examples

$@9|This is the contents of the original subfield $9

$@q|This is the contents of the original subfield $q

Subfield $@ is repeatable in general, but is not allowed in:

CBS tags
Leader(s)
Field 006 Fixed-length Data Elements – Additional Material Characteristics
Field 007 Physical Description Fixed Field
Field 008 Fixed-Length Data Elements
Locally defined MARC 21 tags in the OCLC MARC 21 format (WorldCat)

In a labelled display, the contents of this subfield are displayed from the third character onward, but these subfields are NOT included in the files exported to WorldCat a.o.