Tag Archives: RDF

SHACL, when two wrongs make a right

I have been working with SHACL for a few months in connexion with validating RDF instance data against the requirements of application profiles. There’s a great validation tool created as part of the JoinUp Interoperability Test Bed that lets you upload your SHACL rules and a data instance and tests the latter against the former. But be aware: some errors can lead to the instance data successfully passing the tests; this isn’t an error with the tool, just a case of blind logic: the program doing what you tell it to regardless of whether that’s what you want it to do.
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When RDF breaks records

In talking to people about modelling metadata I’ve picked up on a distinction mentioned by Staurt Sutton between entity-based modelling, typified by RDF and graphs, and record-based structures typified by XML; however, I don’t think making this distinction alone is sufficient to explain the difference, let alone why it matters.¬† I don’t want to get into the pros and cons of either approach here, just give a couple of examples of where something that works in a monolithic, hierarchical record falls apart when the properties and relationships for each entity are described separately and those descriptions put into a graph. These are especially relevant when people familiar with XML or JSON start using JSON-LD. One of the great things about JSON-LD is that you can use instance data as if it were JSON, without really paying much regard to the “LD” part; that’s not true when designing specs because design choices that would be fine in a JSON record will not work in a linked data graph. Continue reading