Field definition and scope:

Field 780 contains a general subdivision term that is equivalent to the 150 topical term or 180 general subdivision field of the same record.  It links headings within a system or from different thesauri or authority files.

The National level record requirement for this field is Optional.

Field 780 is repeatable.

Guidelines for applying content designators:

The content designators identify the subelements occurring in general subdivision headings constructed according to generally accepted thesaurus-building conventions (e.g., Library of Congress Subject Headings, Medical Subject Headings).

A general subdivision may be a topical or language term that is used as a subdivision portion of an extended subject or index term access field in bibliographic records.

A topical or language term that is used as the lead element of an established heading record is contained in a 150 (Heading - Topical Term) field.

For indicator and subfield code definitions and examples, National level (NLR) record requirements, and designator repeatability, see table below:

Position

Description

NLR

Repeatability

Field 780

Subdivision Linking Entry - General Subdivision

O

R

Indicator:

 

 

 

First

Undefined; contains a blank

M

 

 

 

 

 

Second

Thesaurus

M

 

0

Library of Congress Subject Headings/Name authority file

A

 

1

LC subject headings for children's literature

A

 

2

Medical Subject Headings/NLM name authority file

A

 

3

National Agricultural Library subject authority file

A

 

4

Source not specified

A

 

5

Canadian Subject Headings/LAC name authority file

A

 

6

Répertoire de vedettes-matière

A

 

7

Source specified in subfield $2

A

 

 

 

 

 

Subfield code:

 

 

 

$i

Relationship information

A

R

$v

Form subdivision

A

R

$w

Control subfield

A

NR

 

/0  Link display

M

 

 

/1  Replacement complexity

A

 

$x

General subdivision

M

R

$y

Chronological subdivision

A

R

$z

Geographic subdivision

A

R

$0

Authority record control number or standard number

A

R

$1

Real World Object URI

 

R

$2

Source of heading or term

A

NR

$4

Relationship

O

R

$5

Institution to which field applies

A

R

$6

Linkage

A

NR

$8

Field link and sequence number

O

R

 

See:  Examples for this field.

Input conventions:

Punctuation

Spacing

Order of subfields

Relationship codes

Display constant for X80 fields

Display constants for 7XX Linking Entries

Content designator history:

Subfield $i - Relationship information  [new, 2014]

Subfields  $u - Record control number  [obsolete, 1997]  [USMARC only]

$v - Record control number  [redefined, 1995]  [USMARC only]

$0 - Record control number  [new, 1997]

$0 - Record control number  [redefined, 2010]

$v - Form subdivision  [redefined, 1995]  [USMARC only]

$3 - Authority record control number  [obsolete, 1997]  [CAN/MARC only]

In USMARC, from 1993 to 1995, subfield $v was defined as Record control number in the 7XX Heading Linking Entry fields.  When subfield $v was adapted for form subdivisions in MARC bibliographic and authority heading fields in 1995, subfield $v was redefined as Form subdivision and subfield $u was defined as Record control number.  In 1997, subfield $0 was added as Record control number in 5XX and 7XX fields and $u was made obsolete.

Subfield $w/1 - Replacement complexity  [new, 2002]:  In 2002, subfield $w/1 was defined with the following codes:  a (Heading replacement does not require review); b (Heading replacement requires review); and n (Not applicable).

Subfield $1 - Real World Object URI  [new, 2017]

Subfield $4 - Relationship code  [new, 2014]

Subfield $4 - Relationship code  [renamed, 2017] [redescribed, 2017]:  Subfield $4 was renamed to Relationship and redescribed to allow for the recording of relationship URIs in addition to MARC and non-MARC codes.

LC Guidelines:

  780  Subdivision Linking Entry - General Subdivision

DCM Z1 Instructions:

 7XX  Heading Linking Entries

Related MARC fields or documents:

X80  General Subdivisions - General Information

7XX  Heading Linking Entries - General Information

RDA in MARC Authority Data

Source Codes for Vocabularies, Rules, and Schemes:

Subject Heading and Term Source Codes

See also:

7XX  Heading Linking Entries

Variable Data Fields