Dublin Core Metadata Element Set
This is a metadata standard for describing digital objects (including web pages) and often expressed in XML. Commonly referred to as either Dublin Core or DC, it was so named because the first meeting of metadata and web specialists at which it was developed was held in the town of Dublin, Ohio in the USA.
It was a basic design principle to keep the element set small, and any element can be repeated or omitted. It is up to the implementer to decide which elements to use, and to set the level of obligation for each element: mandatory, mandatory if applicable, and optional.
Some of the elements can be sub-divided by using qualifiers to make an element more specific. For example, Description element qualifiers are Table of contents and Abstract. Unlike many other document metadata standards, there is no prescribed order in Dublin Core for presenting or using the elements. In the list below the "title" element was put first and the "rights" element last, but it could just as correctly have been the reverse, or all the elements could have been presented or used in alphabetical order. For some elements, it is recommended that existing encoding schemes are used; thus LCSH, MeSH, DDC, UDC and LCC can all be used in the subject element.
In practice, the basic Dublin Core element set has often proved too restrictive and a number of application profiles (AP) are being developed. Application profile development starts by reviewing definitions of the basic elements and adding to these if necessary to give more guidance on usage within a specific domain or sector. The basic set of elements is also reviewed and additional elements may be proposed, though such proposals are kept to the minimum. If a suitable additional element exists in another application profile, this is used (perhaps with additional qualifiers) in order to maintain consistency.
Basic Dublin Core Element Set
title creator (e.g. author) subject description publisher contributor date resource Type (nature or genre of resource) format (extent and medium) resource Identifier (unambiguous identifier such as DOI or ISBN) source (another resource from which this one is derived) language relation (is version of x, part of x, etc.) coverage (spatial or temporal coverage of the resource) rights
As an example of qualifiers, the Date element has the following qualifiers:
date:created date:valid date:available date:issued date:modified
Example record for an electronic text file available for download from the Project Gutenberg site.
<title> Alice in Wonderland </title> <creator> Lewis Carroll </creator> <subject> Fiction </subject> <publisher> Project Gutenberg </publisher> <date>2000 </date> <format> ASCII file via FTP </format> <identifier> http://prmo.net.pg/.... </identifier>