[RESOLVED] Help needed on web application login!

[eakin]

Hey guys
I am fairly new so would be grateful if anyone could help me out...

i am creating a web application using asp.net with vb.net code which connects to an sql database.

I am trying to configure some code for my login section which basically figures out if a username already exists and then outputs 'username already exists' in a label.

At present it works for the first row in the database
i.e if my database consists of

username <-- this is the colum name
user
user1
user2

then if I try and register a new username called 'user' then everything works and the label is updated with the 'username already exists' label.
but if I try to pick a new username of 'user1' or 'user2' then it doesn't work and it creates a duplicate entry into the database.

I beleive this is because I am not looping through all the usernames although I am not sure how to do this, can someone please submit the modifed code or instruct me on how to do this loop?

my current code is :-

strSQL = "SELECT * FROM users"
objCmd.CommandText = strSQL
objReader = objCmd.ExecuteReader()
If objReader.Read() Then
If objReader.Item("username") = userTextbox.Text Then
levelTextbox.Text = "username already exists"
objReader.Close()
Else
objReader.Close()
strSQL1 = "INSERT INTO users VALUES ( '" + username + "' , ***other fields contianed here (not important)***)"
objCmd.CommandText = strSQL1
objCmd.ExecuteNonQuery()

End If
End If