Since I'm just a beginner in using Ubuntu 18.04 and MySQL 5.7 on it, which is the best and fastest way to do backup of database using terminal? Or do I need to search for it in some files and whatever...
and you will get a text based file that holds any SQL related to that that database: table definition, content. The link will list far more options (you can for instance only dump the structure of the database, include procedures, functions and many more)
The default method would be to use mysqldump.
and you will get a text based file that holds any SQL related to that that database: table definition, content. The link will list far more options (you can for instance only dump the structure of the database, include procedures, functions and many more)