Name
uname — intern a string value as a unique-name (uname) atom
Synopsis
any uname(
|
in value any); |
Description
uname converts value (a narrow
or wide string, or another uname) into a Virtuoso unique-name atom. Unames
are server-wide interned strings: equal unames share the same in-memory
pointer, so comparing them is constant-time and identical values use only
one allocation regardless of how many places refer to them. RDF triples
store IRIs as unames, and the XML and SPARQL machinery use them heavily
for element/attribute names and IRI prefixes.
Pass an existing uname through to obtain it unchanged; pass a narrow or
wide string to intern its value. The result is of type uname
and can be tested with
isuname. Returns
SQL NULL when the input is NULL.