Create Oracle Text Index [CTXRULE Index]

The first step is to create a table of queries that define your classifications. We create a table myqueries to hold the category name and query text:

CREATE TABLE myqueries ( queryid NUMBER PRIMARY KEY, category VARCHAR2(30), query VARCHAR2(2000) );

INSERT INTO myqueries VALUES(1, 'US Politics', 'democrat or republican');
INSERT INTO myqueries VALUES(2, 'Music', 'ABOUT(music)');
INSERT INTO myqueries VALUES(3, 'Soccer', 'ABOUT(soccer)');

Use CREATE INDEX to create the CTXRULE index. You can specify lexer, storage, section group, and wordlist parameters if needed:

CREATE INDEX ON myqueries(query) INDEXTYPE IS CTXRULE PARAMETERS ('lexer lexer_pref storage storage_pref section group section_pref wordlist wordlist_pref');

Assume that incoming documents are stored in the table news:
CREATE TABLE news ( newsid NUMBER, author VARCHAR2(30), source VARCHAR2(30),article CLOB);

You can create a before insert trigger with MATCHES to route each document to another table news_route based on its classification:

BEGIN
-- find matching queries
FOR c1 IN (select category
from myqueries
where MATCHES(query, :new.article)>0)
LOOP
INSERT INTO news_route(newsid, category)
VALUES (:new.newsid, c1.category);
END LOOP;
END;