Long MARC Fields, Limits and Splitting
- Article Type: Q&A
- Product: Aleph
- Product Version: 20
Question
What is Aleph's limit on the size of a single field?
How many characters can a single field accommodate?
When Aleph encounters a long field, how this handled?
Answer
Any single tag is limited to 2000 characters.
Aleph will automatically break any longer incoming tags into multiple occurrences.
“Convert MARC Records - Step 2 (file-02)” breaks fields at logical boundaries (subfields or full words) in versions 16 and up. Please see example attached.
There are the following rules: When the text in one field is longer than 2000 Bytes it is split into several fields beginning with $$9. The first fields are around 1000 Bytes. E.g. when the field has 2800 bytes, it will be split into 2 fields (the first with 1000, the 2nd with 1800). If the field has 3400 bytes, it will be split into 3 fields (the first with 1000, the 2nd with 1000 and the last with 1400).
Separators are the ' -- ' , blanks or full stop. If there is a "word" containing more than 2000 characters like in your example it is cut after 1000 characters. If there are blanks or full stops or ' -- ' in it, the program looks for this to cut the fields.
Additional Information
* When downloading records to the Aleph from OCLC via the oclc_server, Aleph breaks long tags at a fixed position, rather than breaking on a word or subfield boundary. The result is that a broken word displays as two strings, with a space between (for example, "subsurface" becomes "subsu rface").
* Do not use 2709 OCLC conversion (Catalog module > Records tab > Import Records > Convert Records > Convert Procedure drop-down) for records with fields longer than 2000 bytes because this routine does not handle long fields correctly.
* The preferred conversion routine is pc_tab_cat_conv. This is a REMOTE method and information about it is found in System Librarians Guide > Cataloging > Importing Records.
* If there is a convert procedure in the Cataloging module Convert Records with the name "MARC", this is probably already set up to use pc_tab_cat_conv.
Attachment
Category: Cataloging (500)
Subject: Importing records (500)
- Article last edited: 11/15/2013