phpMyAdmin is a feature-rich tool coded in PHP, which will give you full control of a MySQL database. You could do virtually anything - create fields, rows and tables, erase them or modify their content, export or import an entire database or only a particular part of it, and execute MySQL commands. The tool is essential in case you would like to switch web hosting companies, because you could effortlessly create a full backup of a database in different formats (SQL, CSV, XML). You will end up with only one file containing the whole content of the database, so you could download it from the current provider, upload it to the server of the new one and import it via the same tool on their end. Your website shall look exactly the same, because all script applications store their data in a database. With phpMyAdmin you may also conveniently search and replace information of your choice across the whole web site - a word, an expression or a link, for example.