Multiple text indexes on a single database

Question

Hi,
We want to enable text search on one of our databases. Due to the specificity of the database we want to use a custom thesaurus.
I would like to know if there's a way to create different text indexes using different thesaurus and then specify the index to be used in the query(similar to oracle sql hints).
Thanks,
Uma

Answer 1

I don't know how often your data changes or how soon that data needs to be searchable or whether there can be any down time. If you can run a nightly procedure, during which time the data would not be searchable, you can have that procedure synchronize the index, then check all of the indexed tokens against those in your financial terms and those in your stoplist, then add any of the tokens that are not financial terms to your stoplist, then drop and rebuid the index. The new documents will then be searchable. It appears that, in order for the new stopwords to be used, the index must be dropped and recreated, not just rebuilt or synchronized. Please see the example below.
SCOTT@10gXE> CREATE TABLE financial_terms
  2    (word VARCHAR2 (60))
  3  /
Table created.
SCOTT@10gXE> INSERT ALL
  2  INTO financial_terms VALUES ('account')
  3  INTO financial_terms VALUES ('balance')
  4  INTO financial_terms VALUES ('bank')
  5  INTO financial_terms VALUES ('deposit')
  6  INTO financial_terms VALUES ('finance')
  7  INTO financial_terms VALUES ('loan')
  8  INTO financial_terms VALUES ('withdraw')
  9  SELECT * FROM DUAL
10  /
7 rows created.
SCOTT@10gXE> CREATE TABLE financial_documents
  2    (document CLOB)
  3  /
Table created.
SCOTT@10gXE> EXEC CTX_DDL.CREATE_STOPLIST ('non_financial')
PL/SQL procedure successfully completed.
SCOTT@10gXE> CREATE INDEX financial_idx ON financial_documents (document)
  2  INDEXTYPE IS CTXSYS.CONTEXT
  3  PARAMETERS ('STOPLIST non_financial')
  4  /
Index created.
SCOTT@10gXE> CREATE OR REPLACE PROCEDURE check_words
  2  AS
  3  BEGIN
  4    CTX_DDL.SYNC_INDEX ('financial_idx');
  5    FOR r IN
  6        (SELECT token_text
  7         FROM      dr$financial_idx$i,
  8             (SELECT UPPER (word) AS word
  9              FROM      financial_terms
10              UNION ALL
11              SELECT UPPER (spw_word) AS word
12              FROM      ctx_stopwords
13              WHERE  spw_stoplist = 'NON_FINANCIAL')
14         WHERE  token_text = word (+)
15         AND      word IS NULL)
16    LOOP
17        CTX_DDL.ADD_STOPWORD ('NON_FINANCIAL', r.token_text);
18    END LOOP;
19    EXECUTE IMMEDIATE 'DROP INDEX financial_idx';
20    EXECUTE IMMEDIATE
21        'CREATE INDEX financial_idx ON financial_documents (document)
22         INDEXTYPE IS CTXSYS.CONTEXT
23         PARAMETERS (''STOPLIST non_financial'')';
24  END check_words;
25  /
Procedure created.
SCOTT@10gXE> SHOW ERRORS
No errors.
SCOTT@10gXE> INSERT ALL
  2  INTO financial_documents VALUES ('bank account')
  3  INTO financial_documents VALUES ('loan application')
  4  INTO financial_documents VALUES ('test of other words')
  5  SELECT * FROM DUAL
  6  /
3 rows created.
SCOTT@10gXE> COMMIT
  2  /
Commit complete.
SCOTT@10gXE> EXECUTE check_words
PL/SQL procedure successfully completed.
SCOTT@10gXE> SELECT spw_word
  2  FROM   ctx_stopwords
  3  WHERE  spw_stoplist = 'NON_FINANCIAL'
  4  /
SPW_WORD
APPLICATION
OF
OTHER
TEST
WORDS
SCOTT@10gXE> SELECT token_text FROM dr$financial_idx$i
  2  /
TOKEN_TEXT
ACCOUNT
BANK
LOAN
SCOTT@10gXE> SELECT * FROM financial_documents
  2  WHERE CONTAINS (document, 'account OR loan OR test') > 0
  3  /
DOCUMENT
bank account
loan application
SCOTT@10gXE>