Can the column arrangement in a table
affect query performance?
Below is the way my table is created:

MY_ID VARCHAR2(18)
MY_CODE VARCHAR2(12)
EMP_NAME VARCHAR2(4)
EMP_CODE VARCHAR2(2)
EMP_ADD VARCHAR2(2)
EMP_NO VARCHAR2(15)
EMP_RES VARCHAR2(18)
EMP_ST VARCHAR2(1)
HIRE_DATE DATE
CLASS_DATE DATE

This is how the index is created:

Create index my_emp_idx on my_emp (EMP_NO,EMP_CODE,MY_CODE)

NOTE: My select and updates statements uses a
where clause which is always
in the order of the index craetion.

e.g where EMP_NO = and EMP_CODE = and MY_CODE=


QUESTION:
Currently the index is being used correctly
for all the sql's

If I change the way the table is created
using the indexed columns as the
first columns during the table creation
(like the example below) before the other
columns, would this increase the speed of my queries?

EMP_NO VARCHAR2(15)
EMP_CODE VARCHAR2(2)
MY_CODE VARCHAR2(12)
EMP_RES VARCHAR2(18)
HIRE_DATE DATE
CLASS_DATE DATE
EMP_NAME VARCHAR2(4)
MY_ID VARCHAR2(18)
EMP_ADD VARCHAR2(2)
EMP_ST VARCHAR2(1)
MY_ID VARCHAR2(18)