There are at least three ways to backup your MySQL Database :
Execute a database backup query from PHP file.
Run mysqldump using system() function.
Use phpMyAdmin to do the backup.
Execute a database backup query from PHP file
Below is an example of using SELECT INTO OUTFILE query for creating table backup :
To restore the backup you just need to run LOAD DATA INFILE query like this :
It's a good idea to name the backup file as tablename.sql so you'll know from which table the backup file is
Run mysqldump using system() function