public static void Main()
{
Database.SetInitializer(new MigrateDatabaseToLatestVersion<AtmContext, AtmData.Migrations.Configuration>());
using (var atm = new AtmContext())
{
FillInSampleRecords(atm);
// Normal case
Console.WriteLine(WithdrawMoney(atm, "1234567890", "1234", 500));
// Withdrawal of no money
Console.WriteLine(WithdrawMoney(atm, "1234567890", "1234", 0));
// Wrong PIN
Console.WriteLine(WithdrawMoney(atm, "1234567890", "0001", 500));
// Wrong card number
Console.WriteLine(WithdrawMoney(atm, "4444444444", "1234", 500));
// Wrong card number and PIN
Console.WriteLine(WithdrawMoney(atm, "4444444444", "4444", 500));
// Too much money
Console.WriteLine(WithdrawMoney(atm, "1234567890", "1234", 5000));
Console.WriteLine();
Console.WriteLine("Transaction logs:");
foreach (var log in atm.TransactionLogs.Include("Account"))
{
Console.WriteLine("{0} | {1} | {2} | {3}", log.Id, log.Account.CardNumber, log.OldMoney, log.NewMoney);
}
}
}
public static string WithdrawMoney(AtmContext atm, string cardNumber, string cardPin, decimal money)
{
var options = new TransactionOptions();
// Repeatable read - data can be added and read but not modified during a transaction
options.IsolationLevel = IsolationLevel.RepeatableRead;
using (var transactionScope = new TransactionScope(TransactionScopeOption.Required, options))
{
var card = atm.CardAccounts.Where(a => a.CardNumber == cardNumber && a.CardPin == cardPin).FirstOrDefault();
if (card == null)
{
return "The money withdrawal was unsuccessful. The card number or PIN is invalid.";
}
if (card.CardCash - money > 0)
{
decimal oldMoney = card.CardCash;
card.CardCash -= money;
decimal newMoney = card.CardCash;
atm.SaveChanges();
transactionScope.Complete();
LogTransaction(atm, card, oldMoney, newMoney);
return string.Format(
"Successfully withdrew {0} dollars from card {1}. The amount remaining is {2}.",
money,
card.CardNumber.Substring(0, 4).PadRight(10, 'X'),
card.CardCash);
}
else
{
return "The money withdrawal was unsuccessful. There are not enough money in the account.";
}
}
}
private static void LogTransaction(AtmContext atm, CardAccount account, decimal oldMoney, decimal newMoney)
{
var options = new TransactionOptions();
// Snapshot - data can be read but before modifying the value is checked for updates
options.IsolationLevel = IsolationLevel.RepeatableRead;
using (var transactionScope = new TransactionScope(TransactionScopeOption.Required, options))
{
atm.TransactionLogs.Add(new TransactionLog() { Account = account, OldMoney = oldMoney, NewMoney = newMoney });
atm.SaveChanges();
transactionScope.Complete();
}
}
private static void FillInSampleRecords(AtmContext atm)
{
atm.CardAccounts.Add(new CardAccount() { CardNumber = "1234567890", CardPin = "1234", CardCash = 2000 });
atm.CardAccounts.Add(new CardAccount() { CardNumber = "0452368874", CardPin = "4455", CardCash = 1000 });
atm.CardAccounts.Add(new CardAccount() { CardNumber = "8965123476", CardPin = "0000", CardCash = 500.23M });
atm.SaveChanges();
}