TDB OPTIMIZER question:a puzzled of RULE language about " VAR and TERM "

[董宁.阿帕比]

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?

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?

3.       And there are a few explanation and samples on http://jena.apache.org 
.Are there any other tutorial about statistics rule?

         

         THANK!

                                                                                
                                                                                
                                                                                
                               Tony.Dong