Can the text index do it for me?

Question

Hi all,
I have the following requirements und question to oracle text index:
I have saved in the VARCHAR2 column some strings:
CREATE TABLE t1
(STR VARCHAR2(200));
INSERT INTO t1 (STR)
VALUES ('Abcd');
INSERT INTO t1 (STR)
VALUES ('abcd');
INSERT INTO t1 (STR)
VALUES ('Aabcd');
INSERT INTO t1 (STR)
VALUES ('Abcd-ef');
INSERT INTO t1 (STR)
VALUES ('Abcd ef');
INSERT INTO t1 (STR)
VALUES ('Abcd - ef');
INSERT INTO t1 (STR)
VALUES ('Abcd - 12');
INSERT INTO t1 (STR)
VALUES ('Abcd_ef12');
INSERT INTO t1 (STR)
VALUES ('Abcdef');
INSERT INTO t1 (STR)
VALUES ('Abcdgh');
INSERT INTO t1 (STR)
VALUES ('Abcdij');
INSERT INTO t1 (STR)
VALUES ('Abcdklmnop');
COMMIT;Then I create a text index with the following script:
BEGIN
  CTX_DDL.CREATE_PREFERENCE('SUBSTR_PREF','BASIC_WORDLIST');
  CTX_DDL.SET_ATTRIBUTE('SUBSTR_PREF','SUBSTRING_INDEX','TRUE');
  CTX_DDL.CREATE_PREFERENCE('pj_lex', 'BASIC_LEXER');
  CTX_DDL.SET_ATTRIBUTE('pj_lex', 'PRINTJOINS', '-');
  CTX_DDL.CREATE_PREFERENCE('mcds_t1_str', 'MULTI_COLUMN_DATASTORE');
  CTX_DDL.SET_ATTRIBUTE('mcds_t1_str', 'COLUMNS', '''XZX''||STR');
END;
CREATE INDEX IDX_T1_STR ON T1
(STR)
INDEXTYPE IS CTXSYS.CONTEXT
PARAMETERS('wordlist  SUBSTRING_PREF
            LEXER     pj_lex
            DATASTORE mcds_t1_str
            memory    50m')
NOPARALLEL;My requirements are: when I search for "abcd" (WHERE contains (STR, 'XZX'||:var1||'%') > 0):
I should get: Abcd, abcd, Abcd-ef, Abcd ef, Abcd - ef, Abcd - 12, Abcd_ef12, but not Abcdef*, Abcdgh*,*Abcdij*, Abcdklmnop*, Aabcd*
The found text should start with "abcd" (case insensitive), after "abcd" it should have 1 or more characters which start with blank, "-", "_", or some other special character, but should not start with a letter!
Is it possible to achieve it with oracle text index?
Regards

Answer 1

You must define the hypen etc. as SKIPJOINS not as PRINTJOINS.
BTW your create index skript fails due to wrong parameter name.
BEGIN
  CTX_DDL.CREATE_PREFERENCE('SUBSTR_PREF','BASIC_WORDLIST');
  CTX_DDL.SET_ATTRIBUTE('SUBSTR_PREF','SUBSTRING_INDEX','TRUE');
  CTX_DDL.CREATE_PREFERENCE('pj_lex', 'BASIC_LEXER');
  CTX_DDL.SET_ATTRIBUTE('pj_lex', 'SKIPJOINS', '-');
END;
CREATE INDEX IDX_T1_STR ON T1
(STR)
INDEXTYPE IS CTXSYS.CONTEXT
PARAMETERS('wordlist  SUBSTR_PREF
            LEXER     pj_lex'
select *
from t1
where
contains (str, 'abcd') > 0
STR
Abcd ef
Abcd
abcd
Abcd - ef
Abcd - 12
Abcd_ef12 Edited by: chris227 on 06.03.2013 00:58
Example added