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Also known as: QName
A compact identifier combining a namespace prefix with a local name.
DESCRIPTION
Qualified Names abbreviate expanded names using a prefix bound to a namespace and a local part. They are widely used in XML-based technologies and in SPARQL/Turtle prefix declarations. QNames are not full IRIs and may not map uniquely outside their namespace context. CURIEs generalize QNames for broader use in non-XML syntaxes. Careful prefix management avoids collisions and ensures portability in data exchange. Tools typically provide APIs for prefix-to-IRI resolution.
ALTERNATIVE DEFINITIONS
W3C Namespaces in XML 1.0
In XML documents, a QName is used to represent a qualified name.
Anchors QNames in XML namespace usage and context.
W3C XML Schema Part 2: Datatypes
QName represents qualified names.
Defines QName as a datatype in XML Schema.
RELATED TERMS
Namespaces in XML Turtle SPARQL XML Schema JSON-LD Prefix Mapping RDF-XML RDF
COMPETING TERMS
CURIE IRI
KNOWLEDGE AREAS
Semantic & Knowledge Modeling Data Integration & Interoperability Data Modeling
TARGET AUDIENCE
Data Modeler Software Developer Data Engineer Data Architect
EXTERNAL SOURCES
- Wikipedia - QName
- W3C - Namespaces in XML defines QNames
- W3C - Prefix declarations in Turtle
- W3C - SPARQL prefix and QName usage
TOP QUESTIONS
Why are Qualified Names used?
They abbreviate long identifiers with prefixes, making graphs and queries more readable and manageable.
Category: Purpose
How do QNames differ from IRIs?
QNames are contextual abbreviations; IRIs are global identifiers. QName expansion requires prefix bindings.
Category: Comparison
What is a common mistake with QNames?
Assuming QNames are globally unique without prefix context. Always manage namespace bindings.
Category: Mistakes
Are QNames the same as CURIEs?
No, CURIEs generalize QNames and work beyond XML, offering broader applicability.
Category: Clarification
How are QNames used in Turtle?
Turtle uses @prefix declarations and QName-like compact IRIs for readability.
Category: Syntax
Can QNames appear in JSON-LD?
JSON-LD uses compact IRIs via context, which are CURIE-like, not strict XML QNames.
Category: Integration
What governance is needed for QNames?
Maintain a canonical prefix registry and standard namespace policies to avoid collisions.
Category: Governance
How do QNames help in SPARQL?
Prefixes reduce verbosity in queries, improving readability and maintainability.
Category: Benefits
What tools manage prefixes for QNames?
Jena, RDF4J, and many triple stores offer prefix management APIs.
Category: Tooling