Using text on column containing only numbers

Question

Hello,
I need to search in a number column for particular "subnumbers". For
example I have a column with 3453454 in it an I like to searh for the
number "53" in it. I know I could use
select * from table where number_column like '%53%'
but since the table is rather big I'd like to use Oracle Text for it
and query like
select * from table where contains(number_column, 53) > 0
but above query would return NULL after converting the number column
to a varchar2 column! Only full numbers are indexed and therefore only
a search on the full number 3453454 would yield a result. What are my
options to make above query with "contains" clause work?
My initial thought was to create a CTSYS.CTXCONTEXT index.
Column type is Number  10,0
I tried to create a index
create index on table (num_colmn)
indextype is ctsys.context ;
then I get error as follow
RA-06512: at "CTXSYS.DRUE", line 160
ORA-06512: at "CTXSYS.DRVPARX", line 36
ORA-06512: at "CTXSYS.DRUE", line 160
ORA-06512: at "CTXSYS.TEXTINDEXMETHODS", line 364
Thanks in advance

Answer 1

Example:
SCOTT@orcl12c> create table x (y_num number(10,0))
  2  /
Table created.
SCOTT@orcl12c> alter table x add (y_char  varchar2(10))
  2  /
Table altered.
SCOTT@orcl12c> create or replace trigger x_bir
  2    before insert or update of y_num on x
  3    for each row
  4  begin
  5    :new.y_char := to_char (:new.y_num);
  6  end x_bir;
  7  /
Trigger created.
SCOTT@orcl12c> begin
  2    ctx_ddl.create_preference('mywordlist', 'BASIC_WORDLIST');
  3    ctx_ddl.set_attribute('mywordlist','PREFIX_INDEX','TRUE');
  4    ctx_ddl.set_attribute('mywordlist','PREFIX_MIN_LENGTH', '3');
  5    ctx_ddl.set_attribute('mywordlist','PREFIX_MAX_LENGTH', '4');
  6    ctx_ddl.set_attribute('mywordlist','SUBSTRING_INDEX', 'YES');
  7    ctx_ddl.set_attribute('mywordlist','WILDCARD_MAXTERMS', 0);
  8  end;
  9  /
PL/SQL procedure successfully completed.
SCOTT@orcl12c> create index x_idx on x (y_char)
  2  indextype is ctxsys.context
  3  parameters
  4    ('wordlist mywordlist
  5       sync      (on commit)')
  6  /
Index created.
SCOTT@orcl12c> insert into x (y_num) values (3453454)
  2  /
1 row created.
SCOTT@orcl12c> commit
  2  /
Commit complete.
SCOTT@orcl12c> select * from x where contains (y_char, '%53%') > 0
  2  /
     Y_NUM Y_CHAR
   3453454 3453454
1 row selected.