Thanks Andy!
For more detail on question 2:
If a triples DB such as below--
S1 :identifier P1
S2 :identifier P2
S3 :identifier P3
S4 :identifier P4
S5 :identifier P5
The Count to (var :identifier TERM) is 1
The Count to (var :identifier var ) is 5
Is OK?
But if triples is such as these:
S1 :identifier P1
S2 :identifier P1
S3 :identifier P1
S4 :identifier P1
S5 :identifier P1
The Count to (var :identifier TERM) is 1 or 5?,I think is 5.
The Count to (var :identifier var ) is 5.
Is OK?
In addition situation -----if triples like these
S1 :identifier P1
S2 :identifier P1
S3 :identifier P2
S4 :identifier P2
S5 :identifier P3
The Count to (var :identifier TERM) is ?.
Thank Again!
Tony
-----邮件原件-----
发件人: Andy Seaborne [mailto:[email protected]]
发送时间: 2014年6月12日 2:08
收件人: [email protected]
主题: Re: TDB OPTIMIZER question:a puzzled of RULE language about " VAR and TERM "
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
>
>
