Editing Library classification (section)

== Types ==
There are many standard systems of library classification in use, and many more have been proposed over the years. However, in general, classification systems can be divided into three types depending on how they are used:

; Universal schemes: Covers all subjects, e.g. the [[Dewey Decimal Classification]] (DDC), [[Universal Decimal Classification]] (UDC), [[Library of Congress Classification]] (LCC), and [[Colon Classification]] (CC).
; Specific classification schemes: Covers particular subjects or types of materials, e.g. [[Iconclass]] (art), [[British Catalogue of Music Classification]], and [[Dickinson classification]] (music), or the [[NLM Classification]] (medicine).
; National schemes: Specially created for certain countries, e.g. [[Swedish library classification system]], SAB (Sveriges Allmänna Biblioteksförening).

In terms of functionality, classification systems are often described as:

; Enumerative: Subject headings are listed alphabetically, with numbers assigned to each heading in alphabetical order.
; Hierarchical: Subjects are divided hierarchically, from most general to most specific.
; Faceted/analytico-synthetic: Subjects are divided into mutually exclusive orthogonal facets.

There are few completely enumerative systems or faceted systems; most systems are a blend but favouring one type or the other. The most common classification systems, LCC and DDC, are essentially enumerative, though with some hierarchical and faceted elements (more so for DDC), especially at the broadest and most general level. The first true faceted system was the [[colon classification]] of [[S. R. Ranganathan]].<ref>{{Cite journal |last=Ferreira |first=Ana Carolina |last2=Maculan |first2=Benildes Coura Moreira dos Santos |last3=Naves |first3=Madalena Martins Lopes |date=2017 |title=Ranganathan and the faceted classification theory |url=http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-37862017000300279&lng=en&tlng=en |journal=Transinformação |volume=29 |issue=3 |pages=279–295 |doi=10.1590/2318-08892017000300006 |issn=2318-0889}}</ref>