⅁ravityᴚoo𐅠

The Screaming Static in My Mind - Submitted by SeesawSiya

Toasted Sweater - Submitted by lembellique

oooh, this time the Trojan horse is the 019 indicating "duplicates" here's googs: The 019 field in a MARC record imported from the Bibliothèque nationale de France (BnF) or any other source, especially when imported into systems like OCLC WorldCat, is primarily used to manage duplicate records.

OCLC +1

Here is why they are likely using the 019 field:

* OCLC Control Number Cross-Reference: The 019 field is an OCLC-defined field that records the control numbers of records that have been merged and deleted from WorldCat. When BnF records are ingested into a system that uses OCLC records, the system uses the 019 to note that a previous version of the record should be replaced by the current one.

* Preventing Duplicate Data: When the "Duplicate Detection and Resolution" process occurs, the 019 field captures the deleted record's ID to ensure that holdings attached to that old record can be transferred to the new, retained record.

* Tracking Merged Records: It allows library systems to know that a record previously imported from BnF is no longer valid and has been replaced by a more complete or corrected record.

OCLC +1

Key Points about the 019 Field:

* It is not a standard MARC21 bibliographic field but is used extensively for OCLC bibliographic records.

* It contains the OCLC control number (often with an `a` subfield) of the record that was deleted.

* In some cataloging systems (like Ex Libris Alma), the 019 field may need to be added to the metadata configuration to avoid warnings during the import process.

Ex Libris Knowledge Center +2

In short, they are using it for merging and cleaning up duplicate records during the import process to ensure the catalogue stays accurate.