Take Database Backup

MySQL

#To make a backup of the DB
mysqldump -u [uname] -p [pass] db_name > db_backup.sql
 
#To restore the backup
mysql -u [uname] -p [pass] db_name < db_backupfile.sql

Oracle

# To make a backup of the DB
exp username/password file=xyz.dmp
 
# To restore the backup
imp target_username/password FULL=Y file=xyz.dmp