Sorry for this newbie question...

Question

Requirement:
return all documents which does not contain the word "mango"
Code typed:
where contains (ts_files.doc_blob, 'not mango', 1) > 0 )
-->ts_files is the table containing the files.
-->doc_blob is the blob field where files are located.
Returned Error ?:| :
ORA-29902: error in executing ODCIIndexStart() routine
ORA-20000: Oracle Text error:
DRG-50901: text query parser syntax error on line 1, column 2
Can YOU help me, Please ?
Mathew

Answer 1

If you have some other criteria to put before the "not mango", that would work. With a small number of rows, "% not mango" works. However, with a large number of rows with various data, like most such tables have, "% not mango" is likely to result in a wildcard query expansion error. Some alternatives are to use "contains (...) = 0" or " not (contains ...) > 0". These will still use the domain index, but avoid the problem with the wildcard expanding to too many terms. Please see the demonstration below.
SCOTT@orcl_11g> CREATE TABLE ts_files (doc_blob VARCHAR2(60))
  2  /
Table created.
SCOTT@orcl_11g> INSERT INTO ts_files VALUES ('apple')
  2  /
1 row created.
SCOTT@orcl_11g> INSERT INTO ts_files
  2  SELECT 'mango ' || object_name FROM all_objects
  3  /
68584 rows created.
SCOTT@orcl_11g> CREATE INDEX your_index ON ts_files (doc_blob)
  2  INDEXTYPE IS CTXSYS.CONTEXT
  3  /
Index created.
SCOTT@orcl_11g> EXEC DBMS_STATS.GATHER_TABLE_STATS (USER, 'TS_FILES')
PL/SQL procedure successfully completed.
SCOTT@orcl_11g> SET AUTOTRACE ON EXPLAIN
SCOTT@orcl_11g> SELECT * FROM ts_files
  2  WHERE  CONTAINS (ts_files.doc_blob, '% not mango', 1) > 0
  3  /
SELECT * FROM ts_files
ERROR at line 1:
ORA-29902: error in executing ODCIIndexStart() routine
ORA-20000: Oracle Text error:
DRG-51030: wildcard query expansion resulted in too many terms
SCOTT@orcl_11g> SELECT * FROM ts_files
  2  WHERE  CONTAINS (ts_files.doc_blob, 'mango', 1) = 0
  3  /
DOC_BLOB
apple
Execution Plan
Plan hash value: 1960511866
| Id  | Operation                   | Name       | Rows  | Bytes | Cost (%CPU)| Time     |
|   0 | SELECT STATEMENT            |            | 64644 |  1893K| 11343   (1)| 00:02:17 |
|   1 |  TABLE ACCESS BY INDEX ROWID| TS_FILES   | 64644 |  1893K| 11343   (1)| 00:02:17 |
|*  2 |   DOMAIN INDEX              | YOUR_INDEX |       |       | 10781   (0)| 00:02:10 |
Predicate Information (identified by operation id):
   2 - access("CTXSYS"."CONTAINS"("TS_FILES"."DOC_BLOB",'mango',1)=0)
SCOTT@orcl_11g> SELECT * FROM ts_files
  2  WHERE  NOT CONTAINS (ts_files.doc_blob, 'mango', 1) > 0
  3  /
DOC_BLOB
apple
Execution Plan
Plan hash value: 1960511866
| Id  | Operation                   | Name       | Rows  | Bytes | Cost (%CPU)| Time     |
|   0 | SELECT STATEMENT            |            | 64644 |  1893K| 11343   (1)| 00:02:17 |
|   1 |  TABLE ACCESS BY INDEX ROWID| TS_FILES   | 64644 |  1893K| 11343   (1)| 00:02:17 |
|*  2 |   DOMAIN INDEX              | YOUR_INDEX |       |       | 10781   (0)| 00:02:10 |
Predicate Information (identified by operation id):
   2 - access("CTXSYS"."CONTAINS"("TS_FILES"."DOC_BLOB",'mango',1)<=0)
SCOTT@orcl_11g>