ORA-30079: cannot alter database timezone when database has TIMESTAMP WITH LOCAL TIME ZONE columns

ORA-30079: cannot alter database timezone when database has TIMESTAMP WITH
LOCAL TIME ZONE columns


SQL> SELECT DBTIMEZONE FROM DUAL;

DBTIME
------
+00:00

SQL> conn / as sysdba
Connected.
SQL> alter database set time_zone='EST';
alter database set time_zone='EST'
*
ERROR at line 1:
ORA-30079: cannot alter database timezone when database has TIMESTAMP WITH
LOCAL TIME ZONE columns


SQL> alter table OE.ORDERS drop column ORDER_DATE ;

Table altered.

SQL>  alter database set time_zone='EST';

Database altered.