Z39.50 Cataloging

Z39.50 frequently asked questions

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How does OCLC Z39.50 Cataloging compare to OCLC Connexion?

Z39.50 Cataloging does not provide the same functionality as OCLC Connexion. The following list of Z39.50 Cataloging limitations illustrates some of the major differences between the two cataloging services:

  • There is no lock and replace capability for libraries that perform enhance, CONSER, and upgrading activities.
  • Uploading of original cataloging records is not currently available.

Can I access authority files with this service?

Library of Congress name and subject authority records are available for this service via the OCLCAuthoritiesLC database.

Can I display holdings information for individual items?

Yes, you can see holdings for your institution. You can also see other institutions' specific holdings under certain conditions. For details, see the Holdings section of Searching Tips for OCLC Z39.50 Cataloging.

Are "lock and replace" available for "enhance" libraries?

There is no "lock and replace" capability for WorldCat records with OCLC Z39.50 Cataloging.

How do member libraries set holdings?

OCLC Z39.50 Cataloging users have the following options for returning holdings:

Set holdings directly online via Z39.50. This requires that the library’s local Z39.50 client is capable of implementing the OCLC Extended Services Definition of Version 3 (Z39.50-1995).   Libraries should consult with their local system vendor and/or system administrator regarding the functionality and configuration of individual Z39.50 clients. Z39.50 clients can currently be programmed to return holdings information by returning the OCLC control number to the OCLC server. This will attach the library's  institutional symbol to the master WorldCat record. OCLC will also archive a copy of the master record for the library issuing the holdings request.

Return holdings information via batchload or EDX (FTP). Libraries choosing this option must have the ability to export OCLC-derived Z39.50 records from their local systems and deliver these to OCLC via tape or FTP. OCLC Z39.50 records will be identified by the presence of the “Z0” identifier in the MARC 994 field. The 994 field is generated on export from OCLC and OCLC requests that this field be retained when returning holdings information to OCLC. The presence of the 994 field will insure that OCLC Z39.50 derived holdings will be processed correctly. Each record will then be matched using the OCLC record control number during unique key matching.

Libraries that do not currently batchload or deliver holdings information to OCLC via EDX will be required to submit a Batchload Holdings Form through their OCLC regional service provider, along with a sample tape or EDX file for evaluation purposes. Tape and file submittal specifications are included with the batchloading documentation for this service on this Web site. There is an additional fee for the establishment of all new OCLC batchload profiles. Holdings information for OCLC-derived Z39.50 records must always retain the MARC 994 identifier. This will insure optimal sorting and processing of Z39.50 records if these records are combined with records from other sources. Libraries that do not retain the 994 identifier will be required to deliver OCLC Z39.50-derived records as a separate tape or file. Libraries with existing batchload definitions will need to update their profiles and will be required to submit a Batchload Holdings Form to their Regional Networks the first time they submit OCLC-derived Z39.50 holdings. No fee will be assessed if the library is just switching from OCLC Cataloging to OCLC Z39.50 Cataloging as a source of bibliographic records. However, if a library changes its existing automation system or purchases a new one, it will change the way records are exported and this will require a new batchload definition with applicable fees. Consult the batchloading documentation for this service on this web site for specific details on tape and file submittal specifications.

How do member libraries delete holdings?

OCLC supports deleting institution holding symbols via the Z39.50-1995 DatabaseUpdate Extended Service Definition. For more information on deleting holdings, see Z39.50 Database Update Implementation for OCLC Z39.50 Cataloging: Extended Service Definition.


  • All local holdings records (LHRs) associated with a bibliographic record are deleted when holdings are deleted from the bibliographic record. To retain LHRs, move them to another record before deleting holdings from a bibliographic record.
  • Holdings deleted via the Z39.50-1995 DatabaseUpdate Extended Service Definition do not appear in the OCLC Usage Statistics Portal.

Can my library use RCON and search-only authorizations?

Libraries can use RCON and search-only authorizations with this service. However, all transactions processed using these authorizations will be billed at the same rate as transactions that use FULL cataloging authorizations. In addition, libraries using search-only authorizations will not be able to use any of the OCLC Extended Services update functions.

Can I use CJK or other non-Latin alphabet software?

Several non-Latin scripts, including CKJ, can be used with this service. See the Configuration Guide for OCOC Z39.50 Cataloging for additional information.

Can I upload original cataloging records to WorldCat?

OCLC Z39.50 Cataloging does not currently support the addition of cataloging records to WorldCat. OCLC is considering this enhancement for future development.

Can I edit/delete full records?

OCLC Z39.50 Cataloging users currently cannot edit or delete full records from either WorldCat or their archival copy via Z39.50.

Does this service provide access to other OCLC databases?

This service currently access only WorldCat (OLUCWorldCat) and Library of Congress name and subject authorities (OCLCAuthoritiesLC) databases.