SQL Server backup and recovery

The connection test has passed C #2005 and sqlconnection: Data backup
Backup database databasename to disk = 'e: // backup // A. Bak'

Data Recovery
Restore database databasename
From disk = 'e: // backup // A. Bak'

Compressing log files
Backup log databasename with no_log use databasename DBCC shrinkfile (2, 10) DBCC shrinkdatabase
(Databasename, 10)

The file must exist during data backup. Otherwise, an "Access Denied" error may occur. You can create a new file with the same name before backing up the file.
You must connect to the master database to recover other databases during data recovery. Otherwise, the error "the database is in use" may be returned.