Skip to main content
  • Subscribe by RSS
  • Ex Libris Knowledge Center

    What is the difference between union view and union cataloging?

    • Article Type: General
    • Product: Aleph
    • Product Version: 19.01

    What is the difference between union view and union cataloging?

    Please refer to the following documents in the DocPortal:

    "How to Set Up an ALEPH Union Catalog"


    "How to Set Up and Configure Union View for Your OPAC"

    A Union Catalog is a library catalog that contains the holdings of more than one library.
    The Union Catalog often serves as a utility for resource discovery, allowing users to search the catalogs of multiple institutions.

    A Union Catalog contains the holdings of multiple libraries and thus contains multiple records for titles that are held by multiple institutions.
    A Union Catalog does not contain item records. A Union Catalog has embedded holdings instead of linked holdings records.
    Union Catalogs are characterized by frequent loads of records from contributing libraries.

    Other libraries upload their records to the Union Catalog. During the uploading process a unique identifier, which belongs to each record, tells the system whether the record already exists in the database or if it is new. If it already exists in the database it will replace the existing entry, and if it does not already exist then it will be added.

    The system can check whether the record already exists in the union catalog by running cataloging > services > load catalog records > check input file against database (manage-36). This will make a file of new records to be loaded with manage-18: new, and a file of existing records to be loaded with manage-18: replace.

    An example of a union catalog is the Israel Union catalog, available at
    Here member libraries once a month send a file of new and updated records to the administrator of the Union catalog who runs p_manage_36 on the files he receives, then uploads them accordingly with p_manage_18 new and p_manage_18 replace.

    If you do a search on the above union catalog you will see a field "Link to Library" and "Library" which states which library "owns" or sent the record to the Union catalog.
    Frequently, the Union Catalog will offer some form of inter-library loan so that users can request the resources they identify.

    A Union Catalog has an xxx90 library as its bib library.

    A Union View uses one bibliographic library and uses various ways to decide which records should display when there are two records of the "same" record. When two records are the same record there are various ways to determine which one should display based on fields such as ISBN, or the same titles and authors, etc.

    Union View is a tool for creating de-duplicated and merged result sets in the public OPAC.
    Result sets are de-duplicated using pre-constructed record equivalency tables.
    The tables are built using a sophisticated algorithm developed in conjunction with the California Digital Library (CDL) project.

    Union View is ideal for environments where there are two or more institutions sharing a database but not sharing bibliographic records.
    Union View offers a convenient tool for end-user navigation and resource discovery that does not interfere with staff productivity.
    Union View has an xxx01 library as its bib library.

    Additional Information

    union view, union cataloging, OPAC, faq

    • Article last edited: 10/8/2013