Roles in forms validation

The role of forms validation has been very vague, do not know how to do, last night carefully read the next CSDN magazine, a little bit at the bottom of the heart, this morning a csdn, see Shi adult back to a post, is about ASP.net forms validation roles, address is: http:// Www.codeproject.com/aspnet/formsroleauth.asp
Khan, how is e-wen, my e winter poor, but do not know why this unexpectedly was I understand, imitate his doing, unexpectedly success!, the special process and my understanding to write out, hope for and I like the rookie a little help, at the same time some of my understanding may be wrong, I hope you guys can point out, thank you very much, Below I begin to translate the side according to his doing:
1, first of all, we create a new database, called the Web, add a table called users, which has three fields, username field as the primary key, username and password fields set to the federated index, do not know that I understand this right? Please correct me.
CREATE
DATABASE Web
CREATE TABLE Users
(
Username nvarchar (CONSTRAINT) users_pk PRIMARY KEY,
Password nvarchar (128),
Roles nvarchar (64)
)
CREATE INDEX Credentials on users
(
Username
Password
)
We'll add two users to the Users table: Pwqzc 123456 Administrator,user
Pwq 123456 User
The first is the name, the second is the password, the third is the role that the user has, multiple roles, comma separated
2, create a landing page login.aspx
Put two textbox and a button inside, write code in the Click event of the button:
private void Btnlogin_click (object sender, System.EventArgs e)
{
Initialize FormsAuthentication
Formsauthentication.initialize ();
Create a connection and command object
SqlConnection conn = new SqlConnection ("server= (local); Uid=sa;pwd=mydream54win;database=web");
SqlCommand cmd = conn. CreateCommand ();
Cmd.commandtext = "Select roles from Users where Username= @username and password= @password";
Add parameters and assign values to parameters
Cmd. Parameters.Add ("@username", sqldbtype.varchar,64);
Cmd. parameters["@username"]. Value = Username.value;
Cmd. Parameters.Add ("@password", sqldbtype.varchar,128);
Cmd. parameters["@password"]. Value = Password.value;