Create Table Column position matters?

Question

Hi All,
I am just confused the saying that the column positioning in creating tables does not matter for relational database?
Do you agree or disagree.
For me I do not agree. Why?
SQL>  create table a (a char(10),b number);
Table created.
SQL> create table b (b number, a char(10));
Table created.
SQL> insert into a values ('a',1);
1 row created.
SQL> commit;
Commit complete.
SQL> insert into b select * from a;
insert into b select * from a
ERROR at line 1:
ORA-01722: invalid numberSo it does matter.
Thanks

Answer 1

KinsaKaUy? wrote:
Ok maybe I interpreted it in the wrong way : )
Can you help me handle this issue.
I have a table EMP with more than 500 columns, and with 10,000 rows.
The developer asked to modify a column ATTRIBUTE1 from VARCHAR2(10) to NUMBER;
It says that the column needs to be empty to change datatype, so I created a backup:
CREATE TABLE EMP_BAK AS SELECT * FROM EMP;
TRUNCATE TABLE EMP;
ALTER TABLE EMP MODIFY(ATTRIBUTE1 NUMBER);
How can I insert it back using...INSERT INTO EMP SELECT * FROM EMP_BAK;
To aggraviate the situation the designer wants to move the column position from 100th place to 10th place.
Assuming that you can not reason them out, how do you make this task easier?
ThanksInstead of creating a new table and your above mentioned complications you could follow the below method i guess.
ALTER TABLE EMP ADD DUMMY_ATTRIBUTE1 NUMBER;
UPDATE EMP
SET ATTRIBUTE1 = DUMMY_ATTRIBUTE1
WHERE 1=1;
COMMIT;
UPDATE EMP
SET ATTRIBUTE1 = NULL
WHERE 1=1;
COMMIT;
ALTER TABLE EMP MODIFY ATTRIBUTE1 NUMBER;
UPDATE EMP
SET DUMMY_ATTRIBUTE1 = ATTRIBUTE1
WHERE 1=1;
COMMIT;
ALTER TABLE EMP DROP COLUMN DUMMY_ATTRIBUTE1;