EDIT
It appears the user has to enter some data for his profile, otherwise I get this error below. I guess if there is no profile data, the user can not continue to enter data in other tables by default? I do not want to make entering user profile data a requirement to use the rest of the sites functionality, how can I get around this?

Currently I have been testing everything with the same user and everything has been working fine.

However, when I created a new user for the very first time and tried to enter data into my custom table, I get the following error.

The INSERT statement conflicted with the FOREIGN KEY constraint "FK_UserData_aspnet_Profile". The conflict occurred in database "C:\ISTATE\APP_DATA\ASPNETDB.MDF", table "dbo.aspnet_Profile", column 'UserId'. The statement has been terminated.

Not sure why I am getting this error. I have the user controls set up in ASP.NET 3.5 however all I am using is my own table or at least that I am aware of.

I have a custom UserData table that includes the columns:

id, UserProfileID, CL, LL, SL, DateTime

(id is the auto incremented int) The intent is that all users will add their data in this table and as I mentioned above it has been working fine for my original first user I created. However, when i created a new user I am getting this problem.

Here is the code that updates the database.

    protected void Button1_Click(object sender, EventArgs e)
    {

        //connect to database
        MySqlConnection database = new MySqlConnection();
        database.CreateConn(); 

        //create command object
        Command = new SqlCommand(queryString, database.Connection);

        //add parameters. used to prevent sql injection
        Command.Parameters.Add("@UID", SqlDbType.UniqueIdentifier);
        Command.Parameters["@UID"].Value = Membership.GetUser().ProviderUserKey;

        Command.Parameters.Add("@CL", SqlDbType.Int);
        Command.Parameters["@CL"].Value = InCL.Text;

        Command.Parameters.Add("@LL", SqlDbType.Int);
        Command.Parameters["@LL"].Value = InLL.Text;

        Command.Parameters.Add("@SL", SqlDbType.Int);
        Command.Parameters["@SL"].Value = InSL.Text;

        Command.ExecuteNonQuery();
     }

Source Error:

Line 84:
Command.ExecuteNonQuery();