transaction

I am always looking through our code for a previous example of using transactions in .NET, so I am posting the code here. That's what here is for!

        private void TRANSACTION EXAMPLE(int example)
        {
            using (SqlConnection conn = new SqlConnection(dsn))
            {
                conn.Open();
                SqlCommand cmd = conn.CreateCommand();
                SqlTransaction transaction;

                transaction = conn.BeginTransaction("GiveItAName");
                cmd.Connection = conn;
                cmd.Transaction = transaction;
                try
                {
                    //1st query, initializes sql variable
                    string sql = "INSERT INTO someTable etcetc";
                    cmd.CommandText = sql;
                    //define needed parameters is any
                    cmd.ExecuteNonQuery();
                    
                    //next query
                    sql = "UPDATE or WHATEVER QUERY etc etc";
                    cmd.CommandText = sql;

                    // define needed parameters
                    // NOTE you don't have to define any param if it was already defines and used for a previous query
                    cmd.Parameters.Add("@something", SqlDbType.VarChar, 50).Value = exaple;
                    cmd.ExecuteNonQuery();

                    //next query
                    sql = "UPDATE etc etc";
                    cmd.CommandText = sql;
                    cmd.ExecuteNonQuery();

                    // Attempt to commit the transaction.
                    transaction.Commit();
                }
                catch (Exception)
                {
                    // Attempt to roll back the transaction.
                    try
                    {
                        transaction.Rollback();
                    }
                    catch (Exception)
                    {
                        // This catch block will handle any errors that may have occurred
                        // on the server that would cause the rollback to fail, such as
                        // a closed connection.
                        throw;
                    }
                    throw;
                }
           }
     }