Multilingual Linked Open Data Patterns

Opaque URIs


Opaque URIs are resource identifiers which are not intended to represent terms in a natural language.


Opaque URIs can be a good solution when most of the resources are obtained automatically from other systems like relational databases, tables, etc.

This pattern can also be applied when there is a need to have multilingual concepts and it is preferred not to have any language bias.

Using opaque URIs may help to separate the concept from its different labels.


An opaque URI can be:


Opaque URIs can help to emphasize the independence of a resource from its natural language representation. This pattern emphasizes that URIs are not meant for end users but for internal applications.

Depending on the context, URIs with human-readable local names can help users and application developers to manage and debug linked data applications.

Resources with opaque URIs usually depend on labels to hide the URI from the end user.

See also

Opaque URIs are described in [Montiel 11]. There are some well-known vocabularies that employ opaque URIs, like EuroWordnet [Vossen 98] or Agrovoc [Caracciolo 12]. This pattern is associated to the Label everything pattern so that the application can show some information to the end user. This pattern is also related to the Natural Keys pattern, in the sense that Opaque URIs are often the result of a mapping process between some external identifiers which are algorithmically converted to linked data URIs.