SEM_RDFCTX.CREATE

Format

SEM_RDFCTX.CREATE_POLICY(
     policy_name   IN VARCHAR2, 
     extractor     IN mdsys.rdfctx_extractor, 
     preferences   IN sys.XMLType DEFAULT NULL,
     network_owner IN VARCHAR2 DEFAULT NULL,
     network_name  IN VARCHAR2 DEFAULT NULL);

or

SEM_RDFCTX.CREATE_POLICY(
     policy_name       IN VARCHAR2, 
     base_policy       IN VARCHAR2, 
     user_models       IN SEM_MODELS DEFAULT NULL, 
     user_entailments  IN SEM_MODELS DEFAULT NULL,
     network_owner     IN VARCHAR2 DEFAULT NULL,
     network_name      IN VARCHAR2 DEFAULT NULL);

Description

Creates an extractor policy. (The first format is for a base policy; the second format is for a policy that is dependent on a base policy.)

Parameters

policy_name: Name of the extractor policy.
extractor: An instance of a subtype of the RDFCTX_EXTRACTOR type that encapsulates the extraction logic for the information extractor.
preferences: Any preferences associated with the policy.
base_policy: Base extractor policy for a dependent policy.
user_models: List of user models for a dependent policy.
user_entailments: List of user entailments for a dependent policy.
network_owner: Owner of the semantic network. (See Table 1-2.)
network_name: Name of the semantic network. (See Table 1-2.)

Usage Notes

An extractor policy created using this procedure determines the characteristics of a semantic index that is created using the policy. Each extractor policy refers to an instance of an extractor type, either directly or indirectly. An extractor policy with a direct reference to an extractor type instance can be used to compose other extractor policies that include additional RDF models for ontologies.

An instance of the extractor type assigned to the extractor parameter must be an instance of a direct or indirect subtype of type mdsys.rdfctx_extractor.

The RDF models specified in the user_models parameter must be accessible to the user that is creating the policy.

The RDF entailments specified in the user_entailments parameter must be accessible to the user that is creating the policy. Note that the RDF models underlying the entailments do not get automatically included in the dependent policy. To include one or more of those underlying RDF models, you need to include the models in the user_models parameter.

The preferences specified for extractor policy determine the type of repository used for the documents to be indexed and other relevant information. For more information, see Indexing External Documents.

For information about semantic network types and options, see RDF Networks.

Examples

The following example creates an extractor policy using the gatenlp_extractor extractor type, which is included with the Oracle Database support for semantic indexing.

begin
  sem_rdfctx.create_policy (policy_name => 'SEM_EXTR',
                            extractor   => mdsys.gatenlp_extractor());
end;
/

The following example creates a dependent policy for the previously created extractor policy, and it adds the user-defined RDF model geo_ontology to the dependent policy.

begin
  sem_rdfctx.create_policy (policy_name => 'SEM_EXTR_PLUS_GEOONT',
                            base_policy => 'SEM_EXTR',
                            user_models => SEM_MODELS ('geo_ontology'));
end;
/