Horizon lets you specify whether you want to overlay (replace) MARC records in your database with the ones you are importing. Horizon gives you several options that affect the way imported records affect your library’s existing records.
You can choose one of these overlay options on the Multi‑Format Import window for bib and authority records:
• | Never. This keeps the existing matching records in your database, along with the newly imported matching bib records. Horizon logs a warning in an error log called the mistrake file so that you can deal with duplications. If Horizon finds a matching authority record, Horizon logs the authority record in the mistrake table and does not load it into the database as a new record unless the original record was system-generated. Incoming authority records always replace system‑generated authority records. (For more information on system-generated authority records, see About Authority Records.) |
• | Always. This replaces the existing matching records in your database with the newly imported records. |
• | If newer than local date. This replaces existing records with incoming records only if the incoming records are newer, based on the date that the existing record was last changed on your system. |
• | If newer than MARC date. This replaces existing records with incoming records only if the incoming records are newer, based on the MARC date stored in the 005 and 008 tags. |
In a MARC record, the 008 tag contains coded information that describes the record. Positions 14, 15, and 16 of the 008 tag of an authority record indicate whether the record is valid for use as a main or added entry, a subject added entry, or a series added entry. These are the record’s use codes.
If a use code is set to “a,” the authority is valid for that use. If a use code is set to “b,” it is not valid for that use. (For example, if a record’s use codes are set to “aab,” the authority record can be used as a valid author or subject, but not for a series.)
During authority record import, Horizon may make an authority record match using match points or normalized main headings; however, the use codes in the records do not match. To handle this kind of situation, you can choose one of these overlay options:
You can also choose to send a message to the Error Log indicating whether the overlay or merge took place, and if it did not, why not.
You can also choose to send a message to the Error Log indicating whether the overlay or merge took place, and if it did not, why not.
If you choose to overlay when a use code is invalidated and the existing authority record is attached to a bib record for that use type, Horizon overlays the existing record, but does not invalidate the use code. Horizon also sends a message to the Error Log.
• | Create new bib if not overlaid. This lets Horizon create a new bib record when the existing bib record is not overlaid. |
• | Create new auth if not overlaid. This lets Horizon create a new authority record when the existing authority record is not overlaid. |
Depending on your overlay choices, Horizon tries to validate or invalidate an authority record for use as a subject by doing one of these things:
If you chose this |
Horizon does this |
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Always overlay |
Overlays the existing record with the incoming record and changes the record’s use code. |
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Never overlay |
Does not overlay the exiting record. |
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Overlay only if system-generated |
One of these options:
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An incoming record may validate one use code and invalidate another use code in the same record. If you have chosen only one of the validation overlay options so that Horizon gets instructed to both overlay and not overlay that record, Horizon does not overlay the record.
You can choose one overlay option and one delete option for item records:
• | Overlay Items: Never. This keeps the existing matching item records in your database and imports the new matching item records as duplicates. Horizon logs a warning in the mistrake file. |
• | Overlay Items: Always. Horizon overlays any matching item on the database. |
• | Delete Items: Never. Horizon does not delete existing item records from the database. |
• | Delete Items: Always. Horizon deletes the item records from the database. |
Here is a summary of how overlay affects the way Horizon handles MARC records during import:
Type of record |
Overlay enabled |
Overlay not enabled |
Bib record |
The incoming bib record overlays a matching bib record on the database if one exists; otherwise, Horizon creates a new bib record. |
Horizon creates a new bib record. If a matching bib record exists on the database, Horizon records this on the mistrake table. |
Authority record |
The incoming authority record overlays a matching record on the database if one exists; otherwise, Horizon creates a new authority record. |
Horizon creates a new authority record unless the database has a matching record. If a matching authority record exists on the database, Horizon records this on the mistrake table. |
Item record |
The incoming item record overlays a matching item on the database if one exists; otherwise, Horizon creates a new item record. |
Horizon creates a new item record unless the database has a matching record. If a matching item record exists on the database, Horizon records this on the mistrake table. |
All choices you make for overlaying records must be met before Horizon will overlay any record. (For more information, see “Setting Up Import Source Parameters” in the
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