To restore a MySQL database you can use a graphical interface such as phpmysql, however this can be done quite simply from the command line.

From the command line:

First you must login to MySQL

      mysql -u root -p — (the root part assumes root is your mysql username) 

      mysql database_name < database_name.sql 

In the code above, database_name is the name of the database you want to restore, and database_name.sql is the name of the backup file to be restored.

If you are trying to restore a single database from dump of all the databases, you have to let mysql know like this:
mysql –one-database database_name < all_databases.sql