831 Duplicate control field (O;R)

This field is used for database updating purposes only. It shall not be displayed in the WWW interface, nor shall its content be edited by a cataloguer.

Indicator 1: none

Indicator 2: Specifies the type of duplicate reference:

• 0 The record indicated in $a was reviewed by a cataloger and merger of the current and the indicated record into one is deprecated.

• 1 The record indicated in $a is probably a duplicate to the present record and should therefore be revised by a cataloguer.

• 2 The record indicated in $a will be merged to the present record in an updating process, since a cataloguer has considered it referring to the same entity.

$a Record Identifier (M;NR)
Record ID of the record considered duplicate

1. 831 #1$acnp00081480

{"meta": {
    "distinctFrom": ["Record ID ($a)"],
    "sameAs": ["Record ID ($a)"],
    "possibleMatch": [{
        "id": "Record ID ($a)",
        "similarity": "Similarity ($b)"
    }]
}}

• 17.07.2017: Subfields $8, $n and $z are no longer supported, once the CT has been migrated into its new environment