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The library's cataloging staff wants to make sure that their staff is following MARC standards and the library's cataloging rules to ensure consistency and quality in the bib/authority/holdings records that are used in many library workflows and is also made available to library users via discovery service/opac layers. Without validation, the library's catalog maybe difficult to search/browse and with missing/duplicate records.
However this does not mean that the library wants to prevent the record from being created/updated when a validation rule error is identified. In some cases, the library wants the cataloger to know there are validation rule errors and either fix the errors or proceed with saving the record with these errors.
Scenario
A tenant/library may have cataloging rules for MARC bib field 906 (as an example). The library's cataloging practices may state that MARC bib field 906 is required and must always have a $b. In this case, the library's cataloging staff cannot create/derive/edit a MARC bib record via quickMARC that does not have a MARC bib field 906 $b.
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