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Cool IRIs¤


URIs and IRIs are character strings identifying the nodes and edges in the graph. Defining them is an important step in creating an exploitable Knowledge Graph for your Company.

RFC 3986 defines a generic syntax for URIs:

  • <scheme>:<scheme-specific-part>
  • The scheme-specific part is often structured: <authority>/<path>?<query>

URIs are limited to ASCII characters. IRIs (Internationalized Resource Identifiers) allow Unicode (RFC 3987).

The following list of example IRIs demonstrate the broad scope of this concept:

  • ldap://[2001:db8::7]/c=GB?objectClass?one
  • news:comp.infosystems.www.servers.unix
  • tel:+1-816-555-1212
  • telnet://
  • urn:oasis:names:specification:docbook:dtd:xml:4.1.2

Best practices in Corporate Memory¤

A good IRI is unique, stable, simple and manageable.

Define a useful IRI-Scheme that can be used for resources.

  • Define a Base URI which is the common authority for all resources in your graph.
    • Example:
  • Define subspaces where necessary, e.g. for each subproject or domain. Provide a prefix for each subspace. Examples:
    • for hardware artifacts
    • for software artifacts
    • PREFIX cohw: <>
    • PREFIX cosw: <>
  • Based on these, build consistent schemes that define how your IRIs have to be build. Examples:
    •<ProductClass>/<Serialnumber> to identify an individual product
    •<ProductClass>/<Modelnumber> to identify a product model


Do not put a trailing slash at the end of resource IRIs as these cannot be used with prefix definitions in Turtle or SPARQL, which makes them more difficult to use.

More information¤