Text index search issue -- need help

Question

Hi,
We have created a text index using the below script. This is working fine and we are able to retrieve data when we do a search on this with 'contains' clause.
CREATE INDEX ITEM_TXT_IDX ON ITEM
(ITEM_NAME)
INDEXTYPE IS CTXSYS.CONTEXT;However now the problem is we are not able to search with special characters.
when we perform search with below query it doesnt retrieve any record. i guess when we search with special character using text index, it ignores the special characters and performs search
SELECT * FROM item
WHERE contains(item_name, 'AGREE NATURE BALANCED NRML LIQ 300 ML (#', 1) > 0 the below query retrieves record fine as it doesnt have any special character search.
SELECT * FROM item
WHERE contains(item_name, 'AGREE NATURE BALANCED NRML LIQ 300 ML', 1) > 0can anyone pls help?

Answer 1

You need to escape the special characters by either putting \ in front of each special character or putting {} around each token containing special characters. That will cause the contains query to view them as ordinary characters instead of attributing special meaning to them. However, since, by default, they are not tokenized and indexed, they will be ignored and your search will find a string with those characters and a string without those characters. If you want to be able to search for the actual characters, then you need to set them as printjoins in a lexer and use that lexer as a parameter in your index creation. You can see what has been tokenized and indexed by selecting from the token_text column of the dr$your_index_name$i domain index table after index creation. Please see the demonstration below.
SCOTT@orcl_11gR2> -- test environment:
SCOTT@orcl_11gR2> CREATE TABLE item
  2    (item_name  VARCHAR2 (60))
  3  /
Table created.
SCOTT@orcl_11gR2> INSERT ALL
  2  INTO item (item_name) VALUES ('AGREE NATURE BALANCED NRML LIQ 300 ML (#')
  3  INTO item (item_name) VALUES ('AGREE NATURE BALANCED NRML LIQ 300 ML')
  4  INTO item (item_name) VALUES ('OTHER DATA')
  5  SELECT * FROM DUAL
  6  /
3 rows created.
SCOTT@orcl_11gR2> -- without printjoins:
SCOTT@orcl_11gR2> CREATE INDEX ITEM_TXT_IDX
  2  ON ITEM (ITEM_NAME)
  3  INDEXTYPE IS CTXSYS.CONTEXT
  4  /
Index created.
SCOTT@orcl_11gR2> SELECT token_text FROM dr$item_txt_idx$i
  2  /
TOKEN_TEXT
300
AGREE
BALANCED
DATA
LIQ
ML
NATURE
NRML
OTHER
9 rows selected.
SCOTT@orcl_11gR2> SELECT * FROM item
  2  WHERE  contains
  3             (item_name,
  4              'AGREE NATURE BALANCED NRML LIQ 300 ML \(\#',
  5              1) > 0
  6  /
ITEM_NAME
AGREE NATURE BALANCED NRML LIQ 300 ML (#
AGREE NATURE BALANCED NRML LIQ 300 ML
2 rows selected.
SCOTT@orcl_11gR2> SELECT * FROM item
  2  WHERE  contains
  3             (item_name,
  4              'AGREE NATURE BALANCED NRML LIQ 300 ML {(#}',
  5              1) > 0
  6  /
ITEM_NAME
AGREE NATURE BALANCED NRML LIQ 300 ML (#
AGREE NATURE BALANCED NRML LIQ 300 ML
2 rows selected.
SCOTT@orcl_11gR2> -- with printjoins:
SCOTT@orcl_11gR2> BEGIN
  2    CTX_DDL.CREATE_PREFERENCE ('item_lexer', 'BASIC_LEXER');
  3    CTX_DDL.SET_ATTRIBUTE ('item_lexer', 'PRINTJOINS', '(#');
  4  END;
  5  /
PL/SQL procedure successfully completed.
SCOTT@orcl_11gR2> DROP INDEX item_txt_idx
  2  /
Index dropped.
SCOTT@orcl_11gR2> CREATE INDEX ITEM_TXT_IDX
  2  ON ITEM (ITEM_NAME)
  3  INDEXTYPE IS CTXSYS.CONTEXT
  4  PARAMETERS ('LEXER  item_lexer')
  5  /
Index created.
SCOTT@orcl_11gR2> SELECT token_text FROM dr$item_txt_idx$i
  2  /
TOKEN_TEXT
300
AGREE
BALANCED
DATA
LIQ
ML
NATURE
NRML
OTHER
10 rows selected.
SCOTT@orcl_11gR2> SELECT * FROM item
  2  WHERE  contains
  3             (item_name,
  4              'AGREE NATURE BALANCED NRML LIQ 300 ML \(\#',
  5              1) > 0
  6  /
ITEM_NAME
AGREE NATURE BALANCED NRML LIQ 300 ML (#
1 row selected.
SCOTT@orcl_11gR2> SELECT * FROM item
  2  WHERE  contains
  3             (item_name,
  4              'AGREE NATURE BALANCED NRML LIQ 300 ML {(#}',
  5              1) > 0
  6  /
ITEM_NAME
AGREE NATURE BALANCED NRML LIQ 300 ML (#
1 row selected.
SCOTT@orcl_11gR2>