Scripting: Backing Up SQL Server Express Databases
Microsoft SQL Server Express editions do not include SQL Agent so backups cannot be scheduled within SQL Server Management Studio. However the backup can be automated using batch scripts and the Task Scheduler.
When scripting backups it is advisable to also run a Transaction Log backup with the command BACKUP LOG for any databases not using a “Simple” recovery model. Although the BACKUP DATABASE command backs up the entire database, including the contents of the log, the log cannot be shrunk until it has been backed up. If the log does not routinely shrink, it will grow endlessly. The transaction log backup could be output to device 'NUL' if an actual backup file is not required.