Working on a log in script to my webpage

[Pete.....]

Hi all I am working on a log in script for my webpage.

I have the username and the password stored in a PostgreSQL database.

The first I do is I make a html form, where the user can type in his 
username and code, when this is done I want to run the 
script(testifcodeisokay) that verifies that the code and username are the 
right ones ( that means if they match the particular entered username and 
password) If they are then I want to load page1 if they are not I want to 
load the loginpage again.

Login page:

print '''<form action=testifcodeisokay.py'><br>
         <p>Username:<br> <INPUT type="text" NAME="username">
         <p>Code:<br> <INPUT type="text" NAME="code"></p>'''

print '''<p><input type=submit value='Submit'></p></form>'''
print '''</body> </html>'''

This works.
Here I store the entered text in the variables "username" and "code"
I then get the entered value by

testifcodeisokay script

connect = PgSQL.connect(user="user", password="password", host="host", 
database="databse")
cur = connect.cursor()

form = cgi.FieldStorage()
username = form["username"].value
code= form["code"].value

I then want to test if they match the ones in the database

insert_command = "SELECT username, code FROM codetable WHERE 
codetable.username = '%s' AND codetable.code = '%s' " %(username, code)
cur.execute(insert_command)

I should then have found where the entered username,code (on the login page) 
is the same as those in the database.

But now I am stuck.

Does any know how I can then do something like:

If the codes from the loginpage matches the users codes in the db
Then the user should be taken to page1
IF the codes arnt correct the login page should load again.

The program dosnt need to remember who the user is, after the user has been 
loggen in, it is only used to log the user in.

Thanks for your time..