The link for the REPLACE statements should have been http://download-east.oracle.com/docs/cd/B19306_01/server.102/b14200/functions134.htm#SQLRF00697

Chaining or migration can be tollerable as long as your (storage/architecture) design is correct. See also:

http://asktom.oracle.com/pls/ask/f?p=4950:8:18100613647296170221::NO::F4950_P8_DISPLAYID,F4950_P8_CRITERIA:358341515662

After looking up replace, what rules apply for input / ouput datatypes (http://download-east.oracle.com/docs/cd/B19306_01/server.102/b14200/functions134.htm#SQLRF00697)
I did the following:

SQL> select * from v$version;

BANNER
—————————————————————-
Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 – Prod
PL/SQL Release 10.2.0.1.0 – Production
CORE 10.2.0.1.0 Production
TNS for Linux: Version 10.2.0.1.0 – Production
NLSRTL Version 10.2.0.1.0 – Production

5 rows selected.

SQL> create table clob_test
2 (id number(7),
3 name varchar2(20),
4 description clob
5 );

Table created.

SQL> insert into clob_test
2 values (1, ‘ABCD’,'ABCD’)
3 ;

1 row created.

SQL> commit;

Commit complete.

SQL> update clob_test set name = REPLACE( name, ‘ABCD’, ‘ABCDEF’) where ID=1
2 ;

1 row updated.

SQL> update clob_test set description= REPLACE( description, ‘ABCD’, ‘ABCDEF’) where ID=1;

1 row updated.

SQL> select * from clob_test;

ID NAME DESCRIPTION
——— ——————– ——————————————————————————-
1 ABCDEF ABCDEF

1 row selected.

SQL> insert into clob_test
2 values (2, ‘ABCD’,to_clob(‘ABCD’))
3 ;

1 row created.

SQL> commit;

Commit complete.

SQL> select * from clob_test;

ID NAME DESCRIPTION
——— ——————– ——————————————————————————-
1 ABCDEF ABCDEF
2 ABCD ABCD

2 rows selected.

SQL> update clob_test set description= REPLACE( description, ‘ABCD’, ‘ABCDEF’) where ID=2;

1 row updated.

SQL> select * from clob_test;

ID NAME DESCRIPTION
——— ——————– ——————————————————————————-
1 ABCDEF ABCDEF
2 ABCD ABCDEF

2 rows selected.

SQL> update clob_test set description= REPLACE( description, ‘ABCD’, to_clob(‘ABCD’)) where ID=2;

1 row updated.

SQL> select * from clob_test;

ID NAME DESCRIPTION
——— ——————– ——————————————————————————-
1 ABCDEF ABCDEF
2 ABCD ABCDEF

2 rows selected.

SQL> update clob_test set description= REPLACE( description, ‘ABC’, to_clob(‘ABCD’)) where ID=2;

1 row updated.

SQL> select * from clob_test;

ID NAME DESCRIPTION
——— ——————– ——————————————————————————-
1 ABCDEF ABCDEF
2 ABCD ABCDDEF

2 rows selected.

SQL> update clob_test set description= REPLACE( description, to_clob(‘DD’),to_clob(‘D’)) where ID=2;

1 row updated.

SQL> select * from clob_test;

ID NAME DESCRIPTION
——— ——————– ——————————————————————————-
1 ABCDEF ABCDEF
2 ABCD ABCDEF

2 rows selected.