Library of Congress >> MARC >> Classification >> Appendix A

Appendix A - Control Subfields

MARC 21 Classification
October 2003

Subfield Codes
$0 - Record Control Number
$5 - Institution to which Field Applies
$6 - Linkage
$8 - Field Link and Sequence Number

Descriptions of four subfields that are used to link field data to specific institutions or to other fields. These subfields are defined for several ($5 (Institution to which field applies)) or most ($6 (Linkage), $8 (Field link and sequence number)) fields in the format, thus their descriptions are brought together in this appendix. The subfields are included in field level subfield lists wherever they are defined, with pointers to this appendix.


$0 - Record Control Number
System control number of the related classification record preceded by the MARC code, enclosed in parentheses, for the system to which the control number applies. See Organization Code Sources for a listing of organization code sources used in MARC 21 records.
084 0#$alcc
153 ##$aBS580.M6$hThe Bible$hGeneral$hWorks about the Bible$hMen, women and children of the Bible$hBiography$hIndividual Old Testament characters, A-Z$jMoses
700 00$aMoses$c(Biblical leader)$0(DLC)n##79058331
084 0#$alcc
153 ##$aHG3881.5.I58$hFinance$hForeign exchange. International finance$hInternational finance. International monetary system. International banking$hIndividual international financial institutions, A-Z$jInternational Monetary Fund
710 20$aInternational Monetary Fund$0(DLC)n##81052755
084 0#$alcc
153 ##$aPR1588$hEnglish literature$hAnglo-Saxon literature$hIndividual authors and works$hBeowulf$hCriticism$jLanguage, grammar, etc.
730 00$aBeowulf$xLanguage$0(DLC)sh#85013267
$5 - Institution to which Field Applies
MARC code of the institution or organization to which a note applies followed by any specific information about classification at the particular institution. It is used for institution-specific information that may or may not apply to the universal use of the classification record. See Organization Code Sources for a listing of organization code sources used in MARC 21 records.
084 0#$addc$c21
153 ##$a005.262$hGeneralities$hComputer programming, programs, data$kComputer programming and programs$hProgramming for specific types of computers, for specific operating systems, for specific user interfaces$hProgramming for digital microcomputers$jProgramming in specific programming languages
683 1#$iArrange alphabetically by name of programming language, e.g., C++
683 1#$aUse first three letters of programming language to subarrange$5<location identifier>
[The library has its own method for arranging alphabetically, since the instructions are not specific.]
$6 - Linkage
Data that links fields that are different script representations of each other. Subfield $6 may contain the tag number of an associated field, an occurrence number, a code that identifies the first script encountered in a left-to-right scan of the field, and an indication that the orientation for a display of the field data is right-to-left. A regular (non-880) field may be linked to one or more 880 fields that all contain different script representations of the same data. Subfield $6 is structured as follows:
$6[linking tag]-[occurrence number] / [script identification code] / [field orientation code]
Subfield $6 is always the first subfield in the field.
Descriptions of multiscript records, with examples, are in Appendix C; specifications for field 880 are under that field; specifications for character sets and repertoires for scripts are found in MARC 21 Specifications for Record Structure, Character Sets, and Exchange Media.
Linking tag part contains the tag number of the associated field. This part is followed immediately by a hyphen and the two-digit occurrence number part. A different occurrence number is assigned to each set of associated fields within a single record. The function of an occurrence number is to permit the matching of the associated fields (not to sequence the fields within the record). An occurrence number may be assigned at random for each set of associated fields. An occurrence number of less than two digits is right justified and the unused position contains a zero.
When there is no associated field to which a field 880 is linked, the occurrence number in subfield $6 is 00. It is used if an agency wants to separate scripts in a record. The linking tag part of subfield $6 will contain the tag that the associated regular field would have had if it had existed in the record.
680 0#$6880-02$iClass here editions first edited in the 20th century.
880 ##$6680-02/N$i[Explanatory text in Russian]
Occurrence number is followed immediately by a slash (/) and the script identification code. This code identifies the alternate script found in the field. The following codes are used:
Code Script
(3 Arabic
(B Latin
$1 Chinese, Japanese, Korean
(N Cyrillic
(S Greek
(2 Hebrew
880 1#$6153-01/(2/r$j[Caption in Hebrew script]
Entire field need not be in the script identified in subfield $6. If more than one script is present in the field, subfield $6 will contain the identification of the first alternate script encountered in a left-to-right scan of the field.
Note also that the script identification code is used in field 880, subfield $6, but this data element is not generally used for subfield $6 of the associated regular field. In the associated field, the data is assumed to be the primary script(s) for the record.
In a MARC record, the contents of field 880 are always recorded in their logical order, from the first character to the last, regardless of field orientation. 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. (See MARC 21 Specifications for Record Structure, Character Sets, and Exchange Media for a detailed description of field orientation.)
880 ##$6680-00(2/r$a[Scope note in Hebrew script]
[The r indicates the right-to-left orientation of the Hebrew script.]
Note that the orientation code is used in field 880, subfield $6, but this data element is not generally used for subfield $6 of the associated regular field. In the associated field, the data is assumed to be the usual orientation of the primary script(s) for the record.
$8 - Field Link and Sequence Number
Data that identifies linked fields and may propose a sequence for the linked fields. Subfield $8 may be repeated to link a field to more than one other group of fields. The structure and syntax for the field link and sequence number subfield is:
[linking number].[sequence number] \ [field link type]
Linking number is the first data element in the subfield and required if the subfield is used. It is a variable-length whole number that occurs in subfield $8 in all fields that are to be linked. Fields with the same linking number are considered linked.
Sequence number is separated from the linking number by a period "." and is optional. It is a variable- length whole number that may be used to indicate the relative order for display of the linked fields (lower sequence numbers displaying before higher ones). If it is used it must occur in all $8 subfields containing the same linking number.
Field link type is separated from preceding data by a reverse slash “\”. It is a code indicating the reason for the link and it follows the link number, or sequence number if present. In the absence of a field link type, it is assumed that subfield $8 is used for linking and sequencing related 6XX (Notes) or 76X (number building instructions and subarrangements) fields. The use of subfield $8 to maintain the order of these fields is essential to the understanding and application of the subarrangement or table. No explicit field link types have been defined in the MARC 21 Format for Classification Data.
084 0#$alcc
153 ##$aHE394.A$cHE394.Z$hTransportation and communications$hWater transportation$hWaterways$hBy region or country$hUnited States$jRiver improvement. By name of river, A-Z
763 08$iUnder each:
763 10$81.1$a.x$jPeriodicals. Serials$p153
763 10$81.2$a.x3$jGeneral works$p153
763 10$81.3$a.x4$jGeneral special$p153

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