Alter table reaching the max number of char 4000, CLOB? NCLOB?

Question

I have a column is a table defined as a VARCHAR2(4000)
I try to alter the table
alter table sybaapc
MODIFY  SYBAAPC_EXTRACURRICULAR VARCHAR2(5000)but it give me this error
ORA-00910: specified length too long for its datatype
I want the users to be able to enter more information on that column.
It seems that 4000 is the max we are in Oracle 10g
can I changed to CLOB or nclob, we already have data in that table?
What are the implications of changing it to clob or nclob,

Answer 1

Thats becuase the maximum character length for a table column is 4000.
Alternatively you can:
SQL> create table test_1 (col1 VARCHAR2(4000))
  2  /
Table created.
SQL> insert into test_1 values(RPAD('*',4000,'*'));
1 row created.
SQL> commit;
Commit complete.
SQL> alter table test_1 modify (col1 clob);
alter table test_1 modify (col1 clob)
ERROR at line 1:
ORA-22858: invalid alteration of datatype
SQL> alter table test_1 add(col2 clob);
Table altered.
SQL> update test_1 set col2 = col1;
1 row updated.
SQL> commit;
Commit complete.
SQL> alter table test_1 drop column col1;
Table altered.
SQL> alter table test_1 rename column col2 to col1;
Table altered.
SQL> desc test_1
Name                                                  Null?    Type
COL1                                                           CLOB
SQL>
SQL> select * from test_1;
COL1
SQL> Edited by: AP on Aug 24, 2010 7:41 AM