How to create index - Fuzzy Matching and Stemming

Question

Hi,
I have a problem with creating and index for fuzzy matching and stemming with my expect behavious
I Have table customer and column sortname. This table ussally contains values in format: "Surname, FirstName"
"Lenox, Carl"
"Svensson, Max"
"Hamlberg, Ulf"
etc...
1. Previously I have index created like this:
CREATE INDEX IX_CUST_TMP_CTXSORTNAME ON CUSTOMER (SORTNAME) INDEXTYPE IS CTXSYS.CONTEXT PARAMETERS ('SYNC(ON COMMIT)');
If I run:
select * from CUSTOMER where contains(sortname,'Hamlberg') > 0; -- "Hamlberg, Ulf" is returned - OK
select * from CUSTOMER where contains(sortname,'Ulf') > 0; -- "Hamlberg, Ulf" is returned - OK
2. I drop the index and create new one for fuzzy matching and stemming
--NOTE: something is commented out, but I try to run pretty much all the possible varations 
exec ctx_ddl.create_preference('MYYY_SWEDISH_LEXER', 'BASIC_LEXER');
--exec ctx_ddl.set_attribute('MYYY_SWEDISH_LEXER', 'printjoins', '_-');
--exec ctx_ddl.set_attribute('MYYY_SWEDISH_LEXER', 'skipjoins', ',');
exec ctx_ddl.set_attribute('MYYY_SWEDISH_LEXER', 'index_themes', 'NO');
exec ctx_ddl.set_attribute('MYYY_SWEDISH_LEXER', 'index_text', 'YES');
exec ctx_ddl.set_attribute('MYYY_SWEDISH_LEXER', 'index_stems', 'SWEDISH');
exec ctx_ddl.set_attribute('MYYY_SWEDISH_LEXER', 'alternate_spelling', 'SWEDISH');
exec ctx_ddl.set_attribute('MYYY_SWEDISH_LEXER', 'base_letter', 'YES');
exec ctx_ddl.set_attribute('MYYY_SWEDISH_LEXER', 'base_letter_type', 'GENERIC');
exec ctx_ddl.set_attribute('MYYY_SWEDISH_LEXER', 'override_base_letter', 'TRUE');
--exec ctx_ddl.set_attribute('MYYY_SWEDISH_LEXER', 'whitespace', ',');
exec ctx_ddl.create_preference('MYYY_SWEDISH_FUZZY_PREF', 'BASIC_WORDLIST');
exec ctx_ddl.set_attribute('MYYY_SWEDISH_FUZZY_PREF','FUZZY_MATCH','AUTO');
exec ctx_ddl.set_attribute('MYYY_SWEDISH_FUZZY_PREF','FUZZY_SCORE','60');
exec ctx_ddl.set_attribute('MYYY_SWEDISH_FUZZY_PREF','FUZZY_NUMRESULTS','100');
exec ctx_ddl.set_attribute('MYYY_SWEDISH_FUZZY_PREF','SUBSTRING_INDEX','TRUE');
exec ctx_ddl.set_attribute('MYYY_SWEDISH_FUZZY_PREF','STEMMER','AUTO');
create index IX_CUST_TMP_CTXSORTNAME on CUSTOMER (sortname) INDEXTYPE IS CTXSYS.CONTEXT PARAMETERS ('LEXER MYYY_SWEDISH_LEXER Wordlist MYYY_SWEDISH_FUZZY_PREF SYNC(ON COMMIT)');
If I run:
select * from CUSTOMER where contains(sortname,'Hamlberg') > 0; -- "Hamlberg, Ulf" is returned - OK
select * from CUSTOMER where contains(sortname,'Ulf') > 0; -- "Hamlberg, Ulf" is returned - NOT OK - Why it is not returned ??
3. Then I want to use fuzzy for searching names:
a. SELECT score(1), sortname FROM CUSTOMER where CONTAINS(sortname, 'fuzzy({Hamlberg}, 50, 10, weight)',1) > 0; - it should return "Hamlberg, Ulf"
b. SELECT score(1), sortname FROM CUSTOMER where CONTAINS(sortname, 'fuzzy({Ulf}, 50, 10, weight)',1) > 0; - it should return "Hamlberg, Ulf"
c. SELECT score(1), sortname FROM CUSTOMER where CONTAINS(sortname, 'fuzzy({Hamlberg Ulf}, 50, 10, weight)',1) > 0; - it should return "Hamlberg, Ulf"
d. SELECT score(1), sortname FROM CUSTOMER where CONTAINS(sortname, 'fuzzy({Hamlberg, Ulf}, 50, 10, weight)',1) > 0; - it should return "Hamlberg, Ulf"
Is it possible to do that somehow ?
Thx for answers.
Edited by: 906314 on 7.3.2012 4:01

Answer 1

It works fine for me:
SQL> create table customer (sortname varchar2(40));
Table created.
SQL> insert into customer values ('Lenox, Carl');
1 row created.
SQL> insert into customer values ('Svensson, Max');
1 row created.
SQL> insert into customer values ('Hamlberg, Ulf');
1 row created.
SQL> exec ctx_ddl.create_preference('MYYY_SWEDISH_LEXER', 'BASIC_LEXER');
PL/SQL procedure successfully completed.
SQL> --exec ctx_ddl.set_attribute('MYYY_SWEDISH_LEXER', 'printjoins', '_-');
SQL> --exec ctx_ddl.set_attribute('MYYY_SWEDISH_LEXER', 'skipjoins', ',');
SQL> exec ctx_ddl.set_attribute('MYYY_SWEDISH_LEXER', 'index_themes', 'NO');
PL/SQL procedure successfully completed.
SQL> exec ctx_ddl.set_attribute('MYYY_SWEDISH_LEXER', 'index_text', 'YES');
PL/SQL procedure successfully completed.
SQL> exec ctx_ddl.set_attribute('MYYY_SWEDISH_LEXER', 'index_stems', 'SWEDISH');
PL/SQL procedure successfully completed.
SQL> exec ctx_ddl.set_attribute('MYYY_SWEDISH_LEXER', 'alternate_spelling', 'SWEDISH');
PL/SQL procedure successfully completed.
SQL> exec ctx_ddl.set_attribute('MYYY_SWEDISH_LEXER', 'base_letter', 'YES');
PL/SQL procedure successfully completed.
SQL> exec ctx_ddl.set_attribute('MYYY_SWEDISH_LEXER', 'base_letter_type', 'GENERIC');
PL/SQL procedure successfully completed.
SQL> exec ctx_ddl.set_attribute('MYYY_SWEDISH_LEXER', 'override_base_letter', 'TRUE');
PL/SQL procedure successfully completed.
SQL> --exec ctx_ddl.set_attribute('MYYY_SWEDISH_LEXER', 'whitespace', ',');
SQL>
SQL> exec ctx_ddl.create_preference('MYYY_SWEDISH_FUZZY_PREF', 'BASIC_WORDLIST');
PL/SQL procedure successfully completed.
SQL> exec ctx_ddl.set_attribute('MYYY_SWEDISH_FUZZY_PREF','FUZZY_MATCH','AUTO');
PL/SQL procedure successfully completed.
SQL> exec ctx_ddl.set_attribute('MYYY_SWEDISH_FUZZY_PREF','FUZZY_SCORE','60');
PL/SQL procedure successfully completed.
SQL> exec ctx_ddl.set_attribute('MYYY_SWEDISH_FUZZY_PREF','FUZZY_NUMRESULTS','100');
PL/SQL procedure successfully completed.
SQL> exec ctx_ddl.set_attribute('MYYY_SWEDISH_FUZZY_PREF','SUBSTRING_INDEX','TRUE');
PL/SQL procedure successfully completed.
SQL> exec ctx_ddl.set_attribute('MYYY_SWEDISH_FUZZY_PREF','STEMMER','AUTO');
PL/SQL procedure successfully completed.
SQL>
SQL> create index IX_CUST_TMP_CTXSORTNAME on CUSTOMER (sortname) INDEXTYPE IS CTXSYS.CONTEXT PARAMETERS ('LEXER MYYY_SWEDISH_LEXER Wordlist
MYYY_SWEDISH_FUZZY_PREF SYNC(ON COMMIT)');
Index created.
SQL> select * from CUSTOMER where contains(sortname,'Hamlberg') > 0;
SORTNAME
Hamlberg, Ulf
SQL> select * from CUSTOMER where contains(sortname,'Ulf') > 0;
SORTNAME
Hamlberg, Ulf
SQL> SELECT score(1), sortname FROM CUSTOMER where CONTAINS(sortname, 'fuzzy({Hamlberg}, 50, 10, weight)',1) > 0;
  SCORE(1) SORTNAME
        44 Hamlberg, Ulf
SQL> SELECT score(1), sortname FROM CUSTOMER where CONTAINS(sortname, 'fuzzy({Ulf}, 50, 10, weight)',1) > 0;
  SCORE(1) SORTNAME
        44 Hamlberg, Ulf
SQL> SELECT score(1), sortname FROM CUSTOMER where CONTAINS(sortname, 'fuzzy({Hamlberg Ulf}, 50, 10, weight)',1) > 0;
  SCORE(1) SORTNAME
        44 Hamlberg, Ulf
SQL> SELECT score(1), sortname FROM CUSTOMER where CONTAINS(sortname, 'fuzzy({Hamlberg, Ulf}, 50, 10, weight)',1) > 0;
  SCORE(1) SORTNAME
        44 Hamlberg, UlfIs this different from what you see? If so, please show a complete session (as I have) so we can check you're not doing anything wrong.
I don't understand your:
select * from CUSTOMER where contains(sortname,'Ulf') > 0; -- "Hamlberg, Ulf" is returned - NOT OK - Why it is not returned ??
Do you mean "why is it returned?" It's because the "contains" operator matches any word in the original text. That's the whole point of it.