how BLL should call the DAL. in the following code in DAL

public bool Insert(User user)
       {
           SqlConnection con = new SqlConnection(new Connection().GetConnectionString());

           string sql = "INSERT INTO User (Email) values (@Email)";
           con.Open();
           SqlCommand cmd = new SqlCommand(sql, con);
           cmd.Parameters.AddWithValue("@Email", SqlDbType.VarChar);
           cmd.Parameters["@Email"].Value = User.email;
           //cmd.ExecuteNonQuery();

           bool isInserted = cmd.ExecuteNonQuery() > 0;
           return isInserted;

       }

public bool Update(User user)
       {
           SqlConnection con = new SqlConnection(new Connection().GetConnectionString());

           string sql = "UPDATE INTO User (Email) values (@Email)";
           con.Open();
           SqlCommand cmd = new SqlCommand(sql, con);
           cmd.Parameters.AddWithValue("@Email", SqlDbType.VarChar);
           cmd.Parameters["@Email"].Value = User.email;
           //cmd.ExecuteNonQuery();

           bool isUpdated = cmd.ExecuteNonQuery() > 0;
           return isUpdated;

       }