Database Backup and Restore
A database backup creates a copy of the full database. Not all pages are copied to the backup set, only those actually containing data. Both data pages and transaction log pages are copied to the backup set.
A database backup set is used to re-create the database as it was at the time the BACKUP statement completed. If only database backups exist for a database, it can be recovered only to the time of the last database backup taken before the failure of the server or database.