Roles are the easiest way to grant and manage common privileges needed by different groups of database users. Creating roles and assigning provides to roles. Assign each role to group of users. This will simplify the job of assigning privileges to individual users.
By setting the following values in init.ora file.
LOG_ARCHIVE_FORMAT = arch %S/s/T/tarc (%S - Log sequence number and is zero left paded, %s - Log sequence number not padded. %T - Thread number lef-zero-paded and %t - Thread number not padded). The file name created is arch 0001 are if %S is used. LOG_ARCHIVE_DEST = path.
Shut the database
Backup the database
Modify/Include LOG_ARCHIVE_START_TRUE in init.ora file.
Start up the database.
To enable archiving
first shutdown the database in normal mode
then open ur parameter file and include a parameter
archive_log_dest=(give a OS level location)
then come out of it and at OS level create same directory which u have just mentioned in parameter file
then startup mount
then alter database archivelog
then alter database open
in order to know whether ur database is functioning in archive mode or not
type at sql prompt