how to use database function in 3-tier architecture?

Hello my friends

I have a 3-tier layered architecture library automation system.

I am using stored procedure as:

SqlCommand cmd = new SqlCommand("uyeekle", this.conn);
            cmd.CommandType = System.Data.CommandType.StoredProcedure;
            cmd.Parameters.AddWithValue("@uyeadi", EklenecekKisi.uyeadi);
            cmd.Parameters.AddWithValue("@uyesoyadi", EklenecekKisi.uyesoyadi);

       

I want to use (call, return) database function.

I will send @userid and get all the properties as a table (useraddress,telephone,etc) . So how could I use it?  I don't know.

Any idea, help, example will be so helpful. thanks.