mysqldump take the backup by default  all the triggers but NOT the stored procedures and functions.  We can solve this issue with  2 mysqldump parameters:

• –routines - FALSE by default
• –triggers - TRUE by default

It means that if we want to include in an existing backup script also the triggers and stored procedures we only need to add the –routines command line parameter:

mysqldump --routines <databasename>  > backup.sql