Oracle Database Discussions

hello, i am a novice in oracle 10g. recently installed in my organisation.


i needed to resize my redolog files in no archive log mode. so i sucessfully resized redo02 and redo03 which were inactive.redo01 is the active log file.
now they are in unused state. now i wanted to switch log files in order to make redo1 inactive , but i encountered the following error.
( i have connected as sysdba and startup mount exclusive is done)


sql>alter system switch log files;
ORA1109 error:
database not open

what to do please suggest me before monday