On 11/06/14 08:03, DongNing(董宁.阿帕比) wrote:
Hi all:
I am a beginner of jena,I am studying at TDB’S optimizer. About
Statistics rule.
1. I think TERM and VAR’s difference is VAR represent a variant
in sparql. TREM only represent the probable value in the DB, it don’t
represent a variant in sparql.
Is that right?
Yes - TERM means "will be bound at this point"
2. For a statics graph DB(triples are fixed,do not changed)
Count to (var :identifier TERM) and Count to ( Var :identifier var)
should be same?
No.
(var :identifier TERM) should be an estimate of what the cardinality
when there is a specific value. (var :identifier var) would be count of
all uses of :identifier.
if :ifp is an inverse function property,
(?x :ifp TERM) is one.
3. And there are a few explanation and samples on
http://jena.apache.org .Are there any other tutorial about statistics
rule?
Only the code I'm afraid.
Andy
THANK!
Tony.Dong
