Verifying form data - PHP

trim ($first_name);

if (ereg(".", $first_name) == 1)
{
echo "First name: ", "$first_name";
$verify = "OK";
}
else
{
print ("<b>Error:</b> A first name is required.");
$verify = "bad";
}

ereg returns either a "0" (false) or a "1" (true).

The dot . or period is a regular expression wild card meaning "any character."

(ereg(".", $first_name) == 1) means "the variable '$first_name' contains anything". If this expression is true, then the first name is printed, and the variable $verify is set to "OK".

The else argument executes when ereg returns "0" (false).

There are three other versions of the ereg function.

1. ereg_replace uses three arguments: the first is the pattern to search for, the second is the pattern to replace the first pattern, and the third is where to search (a variable).
2. eregi is the same as ereg, except that it's not case-sensitive (i.e., it doesn't differentiate upper- and lower-case letters).
3. eregi_replace is not case sensitive

The line if (ereg(".", $first_name) == 1) can be simplified to if ($first_name). I used the longer form to show how to use ereg in a simple example.

mysql_connect (localhost, username, password);
mysql_select_db (dbname);
$result = mysql_query ("SELECT * FROM tablename
WHERE USER_NAME = '$USER_NAME'
");
if ($row = mysql_fetch_array($result))
{
print ("<b>Error:</b> The user name <b>");
print ("$USER_NAME");
print ("</b> has been taken.  Go back and enter a new user name.");
print ("<p>");
$verify = "bad";
}
else
{
print ("User name: ");
print ("$USER_NAME");
}