Adding columns to tables?

I am creating a GUI for a company for editing the database. The forms allow the user to input the amount of columns to be in the table as well as the table name. The next page brings up a form with as many text boxes as columns specified by the user. The problem comes in when I send this information to MySQL. I need to add the variables to the CREATE TABLE statement through another loop, but you can only have CREATE TABLE once. I figured a way to get around this was to create the table then loop the command to add a column at a time. Is there any way to add a column to a database?

<?

$hostname = "*****";
$username = "*****";
$password = "*****";
$dbName = "*****";

MYSQL_CONNECT($hostname, $username, $password) OR DIE("Unable to connect to database");

@mysql_select_db("$dbName") or die("Unable to select database");

$query = "ALTER table tablename ADD birthday DATE";


$result = MYSQL_QUERY($query);

PRINT "***** $result *******";

PRINT "Your databse altered.";
MYSQL_CLOSE();

?>

This should work.

You can dynamically create you query:

$query="create table $table_name (";
for ($i=1;$i<=$numofcols;$i++)
{
$query.=$columdefinition . " ,";
}