Using char type as ID

Question

- create table test (id char(25), value varchar2(100));
- insert into test valus('1', 'my test value'); commit;
(sqlplus> select * from test where id = 1; -- The row is returned
- Create apex page with two text fields test_id, test_value;
- set the source of test_value to:
select value from test where id = :test_id;
- call this page by a url. Passing in the value to test_id.
** Why will the select not work to populate the test_value item?
** If I change the underlying table id type to (number or varchar) it works.
** I know char as an ID is not ideal. Question comes from a modeling mistake.

Answer 1

Hi,
Because APEX is PL/SQL based it will bind the variables.For example:
SQL> desc x;
Name Null? Type
C1 CHAR(25)
C2 VARCHAR2(200)
SQL> select * from x;
C1 C2
1 Hello
SQL> select * from x where c1 = '1'; <------------ No spaces in sqlplus
C1 C2
1 Hello
SQL> variable target varchar2(25)
SQL> exec :target := '1' <------------------- No spaces n bind variable
PL/SQL procedure successfully completed.
SQL> SELECT * FROM x WHERE c1 = :target;
no rows selected
SQL> exec :target := '1 ' <---- Add 24 spaces
PL/SQL procedure successfully completed.
SQL> SELECT * FROM x WHERE c1 = :target;
C1 C2
1 Hello
So when binding an exact match is required.
I think you would be better of changing them to varchars or if they are really numbers then change them to a number.
If you allow an implicit conversion from 1 to '1' then performance my become an issue as any index for the other type would not be used.
Regards