hmm, I'm not sure what you mean. You want a PHP app to build your database from a exported .sql file?
If so, you can just load the SQL from the backup file as a query and execute the query. When you export as SQL the SQL code in the file will execute as a query.
So basically build your fopen and do
PHP Code:
// Connec to SQL
.......
// Open/Read file
$fp = fopen("sqlfile.sql","r");
$query = fread($fp);
// Execute the query
$results = mysql_query($query);
// close your connects
......