Rename column name

Question

Can i rename column name of a table. If so how to do it????

Answer 1

before 9i
Renaming a column in table:
==========================
This is possible by updating the "name" column of the col$. To reflect this
change in the system views, run catalog.sql and catproc.sql.
Here is an example:
SQL> create table test(
x number,
y varchar2(10),
z varchar2(10));
SQL> insert into test values (12,'Child','BLUE');
SQL> insert into test values (34,'Mens','BROWN');
If you wanted to rename column "x" as column "x1" then do the following.
The first step is to identify the object number for the table (as SYS):
SQL> select obj# from obj$
where name='TEST' and owner#=9;
OBJ#
======
58217
Now identify the column numbers for the table:
SQL> select obj#, col#, name from col$ where obj#=58217;
OBJ# COL# NAME
58217 1 X
58217 2 Y
58217 3 Z
To change the name, a simple update statement will suffice:
update col$ set name='X1'
where obj#=58217 and col#=1;
To reflect the change in system views, run catalog and catproc (unix) eg:
svrmgr> @$ORACLE_HOME/rdbms/admin/catalog
svrmgr> @$ORACLE_HOME/rdbms/admin/catproc
Now when a describe of the table is done:
SQL> desc test;
Name Null ? Type
X1 NUMBER
Y VARCHAR2(10)
Z VARCHAR2(10)
Similarly, selecting from the table and querying views such as
DBA_TAB_COLUMNS shows the new column name.
NOTE: Before changing column names, drop any indexes,
foreign keys and primary constraints that might be on
the column. These can be re-created later.