There are different types of library catalogues:
- Local library catalogues ("Online Catalogue" or "OPAC" = "Online Public Access Catalogue"):
In a local library catalog the media of a library are listed. You can find out where to find them on the shelf (shelf mark=location) and whether they are currently available.
Often an electronic user account with borrowing functions is available (e.g. renewal).
In the current catalogues you will often find a link to the table of contents of a book or to an abstract as an additional service.
As a rule, you can search a local library catalogue only for the titles of books, journal titles, DVDs, e-books and other unindependent literature. You usually cannot search for the titles of articles (dependent literature). For this you need a specialist reference database.
- Regional/supra-regional library union catalogues and meta catalogues:
For the supply of literature there are library union catalogues, in which the stocks of several libraries or different types of literature are listed.
- Karlsruhe Virtual Catalogue KVK (meta search for books in all libraries in Germany + search in bookstores + search in worldwide library catalogues)
- Electronical Journals Catalogue EZB (over 30 000 electronic journals are listed; a traffic light system shows you the activation status of the often fee-based subscriptions)
- Journal Database ZDB (database of all journals available in German libraries; tool of the interlibrary loan departments in libraries)
In meta catalogues, a loss of information can occur during a search because of the different structures of the databases addressed. For a literature search aimed at completeness, an additional search in individual local catalogues or information tools is therefore recommended.