HFEEDBACK

Generates hierarchical query feedback information (broader term, narrower term, and related term) for the specified query.

Broader term, narrower term, and related term information is obtained from the knowledge base. However, only knowledge base terms that are also in the index are returned as query feedback information. This increases the chances that terms returned from HFEEDBACK produce hits over the currently indexed document set.

Hierarchical query feedback information is useful for suggesting other query terms to the user.

Syntax

CTX_QUERY.HFEEDBACK(
           index_name     IN VARCHAR2,
           text_query     IN VARCHAR2,
           feedback_table IN VARCHAR2,
           sharelevel     IN NUMBER DEFAULT 0,
           feedback_id    IN VARCHAR2 DEFAULT NULL,
           );

index_name

Specify the name of the index for the text column to be queried.

text_query

Specify the query expression to be used as criteria for selecting rows.

feedback_table

Specify the name of the table used to store the feedback terms.

See Also: For more information about the structure of the explain table, see "HFEEDBACK Table" in Appendix B.

sharelevel

Specify whether feedback_table is shared by multiple HFEEDBACK calls. Specify 0 for exclusive use and 1 for shared use. This parameter defaults to 0 (single-use).

When you specify 0, the system automatically truncates the feedback table before the next call to HFEEDBACK.

When you specify 1 for shared use, this procedure does not truncate the feedback table. Only results with the same feedback_id are updated. When no results with the same feedback_id exist, new results are added to the feedback table.

feedback_id

Specify a value that identifies the feedback results returned by a call to HFEEDBACK when more than one HFEEDBACK call uses the same shared feedback table. This parameter defaults to NULL.

Example

Create HFEEDBACK Result Table

Create a result table to use with CTX_QUERY.HFEEDBACK as follows:

 
  CREATE TABLE restab ( 
    feedback_id VARCHAR2(30), 
    id          NUMBER, 
    parent_id   NUMBER, 
    operation   VARCHAR2(30), 
    options     VARCHAR2(30), 
    object_name VARCHAR2(80), 
    position    NUMBER, 
    bt_feedback ctx_feedback_type, 
    rt_feedback ctx_feedback_type, 
    nt_feedback ctx_feedback_type 
  ) NESTED TABLE bt_feedback STORE AS res_bt 
    NESTED TABLE rt_feedback STORE AS res_rt 
    NESTED TABLE nt_feedback STORE AS res_nt; 
 

CTX_FEEDBACK_TYPE is a system-defined type in the CTXSYS schema.

See Also: For more information about the structure of the hfeedback table, see "HFEEDBACK Table" in Appendix B.

Call CTX_QUERY.HFEEDBACK

The following code calls the hfeedback procedure with the query computer industry.

BEGIN 
ctx_query.hfeedback (index_name     => 'my_index', 
                     text_query     => 'computer industry', 
                     feedback_table => 'restab', 
                     sharelevel     => 0, 
                     feedback_id    => 'query10' 
                    ); 
END; 

Select From the Result Table

The following code extracts the feedback data from the result table. It extracts broader term, narrower term, and related term feedback separately from the nested tables.

DECLARE 
  i NUMBER; 
BEGIN 
  FOR frec IN ( 
    SELECT object_name, bt_feedback, rt_feedback, nt_feedback  
    FROM restab 
    WHERE feedback_id = 'query10' AND object_name IS NOT NULL 
  ) LOOP 
 
    dbms_output.put_line('Broader term feedback for ' || frec.object_name || 
':'); 
    i := frec.bt_feedback.FIRST; 
    WHILE i IS NOT NULL LOOP 
      dbms_output.put_line(frec.bt_feedback(i).text); 
      i := frec.bt_feedback.NEXT(i); 
    END LOOP; 
 
    dbms_output.put_line('Related term feedback for ' || frec.object_name || 
':'); 
    i := frec.rt_feedback.FIRST; 
    WHILE i IS NOT NULL LOOP 
      dbms_output.put_line(frec.rt_feedback(i).text); 
      i := frec.rt_feedback.NEXT(i); 
    END LOOP; 
 
    dbms_output.put_line('Narrower term feedback for ' || frec.object_name || 
':'); 
    i := frec.nt_feedback.FIRST; 
    WHILE i IS NOT NULL LOOP 
      dbms_output.put_line(frec.nt_feedback(i).text); 
      i := frec.nt_feedback.NEXT(i); 
    END LOOP; 
 
  END LOOP; 
END;

Sample Output

The following output is for the example above, which queries on computer industry:

Broader term feedback for computer industry: 
hard sciences 
Related term feedback for computer industry: 
computer networking 
electronics 
knowledge 
library science 
mathematics 
optical technology 
robotics 
satellite technology 
semiconductors and superconductors 
symbolic logic 
telecommunications industry 
Narrower term feedback for computer industry: 
ABEND - abnormal end of task 
AT&T Starlans 
ATI Technologies, Incorporated 
ActivCard 
Actrade International Ltd. 
Alta Technology 
Amiga Format 
Amiga Library Services 
Amiga Shopper 
Amstrat Action 
Apple Computer, Incorporated
.....





Note:



The HFEEDBACK information you obtain depends on the contents of your index and knowledge base and as such might differ from above.