Let me start with a more clear example (May be this would make the explanation clearer).

The purpose behind the rule (I want) is something like:
If I query for all instaces for ClassA that have the value of the property has_PropertyA as Open, then it should also give me all the instances that have a value for the property has_PropertyB as HIGH.

So, the rule I wrote was:

insert into mdsys.rdfr_RuleBase1 values

( 'Rule1' ,

            '( ?instance rdf:type :ClassA)

             (?instance :has_PropertyB ?b) (?b :hasValue ?d)

             (?instance :has_PropertyA ?a) (?a :hasValue ?c)',



            'REGEXP_like(d, ''HIGH'')' ,



            '(?instance :has_PropertyA ?a) (?a :hasValue "Open")' ,



            sdo_rdf_aliases(...)

          )

);

And, what I want when I query for the instances with PropertyA as Open (using the above rule), is

       (1) instances with propertyA=Open [This is as asked] 

            PLUS

       (2) instances with propertyB=HIGH [This is extra but related info that I need]

(means an effective propertyA=Open OR propertyB=HIGH)

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But when queried, it gives a list of triples, all of which has propertyA as Open. I think it is due to my rule, and the way Oracle 10g does the inference.
=======================================================

The way Oracle 10g handles this inference mechanism through Rules is:

     Each rule has an IF part and THEN part. It finds all the triple patterns that match the IF pattern and then for each of these, it creates a new triple pattern with the values specified in the THEN part. This is done while creating the RulesIndex for each ‘RuleBase-Model’ Combination. So, it means that it pre computes all the inferred triples (creating them as explained above).

For Example:

Actually, in the model, the instance with Id say ID0098 has propertyB=HIGH and propertyA=NOTOPEN. [This is similar to the actual instance value in the persisted model].
But, as this pattern matches the IF part of the Rule, it simply creates a new pattern having an instance with Id ID0098, propertyB=HIGH and replacing propertyA value as ‘Open’ (as specified in the THEN part of the Rule).

Hence when we query for the instances with propertyA=‘Open’ using our custom rule base, it simply executes a SQl statement and retrieves all the ‘Open’ propertyA patterns from both the Actual Model and the Inferred (Pre-computed) triples.

Your inputs are welcome. Tell me if I am still unclear. (I had to hide the details/data due to confidentiality).

Thanks
Bhaskar