public static void Main()
{
using (var firstDbContext = new NorthwindEntities())
{
var firstEmployeeFromFirstDbContext = firstDbContext.Employees.First();
Console.WriteLine("First user see: {0}", firstEmployeeFromFirstDbContext.FirstName);
firstEmployeeFromFirstDbContext.FirstName = "First";
Console.WriteLine("First user changes the name with new value: {0}\n", firstEmployeeFromFirstDbContext.FirstName);
firstDbContext.SaveChanges();
using (var secondDbContext = new NorthwindEntities())
{
var firstEmployeeFromSecondDbContext = secondDbContext.Employees.First();
Console.WriteLine("Second user see: {0}", firstEmployeeFromSecondDbContext.FirstName);
firstEmployeeFromSecondDbContext.FirstName = "Second";
Console.WriteLine("Second user changes the name with new value: {0}\n", firstEmployeeFromSecondDbContext.FirstName);
secondDbContext.SaveChanges();
}
Console.WriteLine("After all changes:");
Console.WriteLine("First user see: {0}\n", firstEmployeeFromFirstDbContext.FirstName);
}
using (var northwindEntities = new NorthwindEntities())
{
Console.WriteLine("Actual result: {0}", northwindEntities.Employees.First().FirstName);
}
}
private static void StartSecondConnection(NorthwindEntities firstConnection)
{
using (var secondConnection = new NorthwindEntities())
{
PrintWhatSecondUserSees(secondConnection);
firstConnection.SaveChanges();
secondConnection.SaveChanges();
PrintWhatSecondUserSeesAfterChanges(secondConnection);
}
}
public static int InsertCustomer(Customer customer)
{
var affectedRows = 0;
using (var db = new NorthwindEntities())
{
db.Customers.Add(customer);
affectedRows = db.SaveChanges();
}
return affectedRows;
}
public static int DeleteCustomer(string customerId)
{
using (var dbContext = new NorthwindEntities())
{
var customer = dbContext.Customers.Find(customerId);
dbContext.Customers.Remove(customer);
int affectedRows = dbContext.SaveChanges();
return affectedRows;
}
}
public static int ModifyCustomerCompanyName(string customerId, string newCompanyName)
{
using (var dbContext = new NorthwindEntities())
{
var customer = dbContext.Customers.Find(customerId);
customer.CompanyName = newCompanyName;
int affectedRows = dbContext.SaveChanges();
return affectedRows;
}
}
public static int ModifyCustomerAddress(string customerID, string newAddress)
{
var affectedRows = 0;
using (var db = new NorthwindEntities())
{
var targetCustomer = db.Customers.Find(customerID);
targetCustomer.Address = newAddress;
affectedRows = db.SaveChanges();
}
return affectedRows;
}
private static int TestWithTransaction()
{
var affectedRows = 0;
var customerId = "RATTC";
var employeeId = 5;
var invalidEmployeeId = 5000;
using (var dbContext = new NorthwindEntities())
{
using (var transaction = dbContext.Database.BeginTransaction())
{
try
{
// To test with invalid data and see what happens, change employeeId with invalidEmployeeId
// then the transaction will rollback and there will be no added orders
var firstOrder = new Order()
{
CustomerID = customerId,
EmployeeID = employeeId
};
dbContext.Orders.Add(firstOrder);
var secondOrder = new Order()
{
CustomerID = customerId,
EmployeeID = employeeId
};
dbContext.Orders.Add(secondOrder);
affectedRows = dbContext.SaveChanges();
transaction.Commit();
Console.WriteLine("- Finish successfully => Commit transaction");
}
catch (Exception)
{
transaction.Rollback();
Console.WriteLine("- Exception: Finish Unsuccessfully => Rollback transaction");
}
}
}
return affectedRows;
}
public static int DeleteCustomerById(string customerID)
{
var affectedRows = 0;
using (var db = new NorthwindEntities())
{
Customer customerToDelete = db.Customers.Find(customerID);
if (customerToDelete != null)
{
db.Customers.Remove(customerToDelete);
affectedRows = db.SaveChanges();
}
}
return affectedRows;
}
public static int DeleteCustomer(string customerId)
{
var affectedRows = 0;
using (var dbContext = new NorthwindEntities())
{
var customersToDelete = dbContext.Customers.Where(c => c.CustomerID == customerId);
if (customersToDelete.Count() > 0)
{
foreach (var customer in customersToDelete)
{
dbContext.Customers.Remove(customer);
}
}
affectedRows = dbContext.SaveChanges();
}
return affectedRows;
}
public static int InsertCustomer(
string customerID,
string companyName,
string contactName = null,
string city = null,
string contactTitle = null,
string address = null,
string region = null,
string postalCode = null,
string country = null,
string phone = null,
string fax = null)
{
var newCustomer = new Customer
{
CustomerID = customerID,
CompanyName = companyName,
City = city,
ContactName = contactName,
ContactTitle = contactTitle,
Address = address,
Region = region,
PostalCode = postalCode,
Country = country,
Phone = phone,
Fax = fax,
};
using (var dbContext = new NorthwindEntities())
{
dbContext.Customers.Add(newCustomer);
int affectedRows = dbContext.SaveChanges();
return affectedRows;
}
}
/// <summary>
/// Started the transaction explicitly. We have options to commit / roll-back transactions.
/// </summary>
private static int TestOnExplicitlyStartedTransaction()
{
var affectedRows = 0;
var customerId = "VINET";
var employeeId = 5;
var invalidEmployeeId = int.MaxValue;
using (var dbContext = new NorthwindEntities())
{
using (var transaction = dbContext.Database.BeginTransaction())
{
try
{
#region [Add Orders]
// This cause an error
var firstOrder = new Order()
{
CustomerID = customerId,
EmployeeID = invalidEmployeeId // employeeId
};
dbContext.Orders.Add(firstOrder);
var secondOrder = new Order()
{
CustomerID = customerId,
EmployeeID = employeeId
};
secondOrder.Order_Details.Add(new Order_Detail()
{
OrderID = secondOrder.OrderID,
ProductID = 5,
UnitPrice = 12.34m,
Quantity = 100,
Discount = 0.2f
});
dbContext.Orders.Add(secondOrder);
#endregion
affectedRows = dbContext.SaveChanges();
// Finish successfully => Commit transaction
transaction.Commit();
// Test to Rollback() insted of Commit() and you will see that the changes are rolled-back
//transaction.Rollback();
Console.WriteLine("- Finish successfully => Commit transaction");
}
catch (Exception)
{
// Finish Unsuccessfully => Rollback transaction
transaction.Rollback();
Console.WriteLine("- Exception: Finish Unsuccessfully => Rollback transaction");
}
}
}
return affectedRows;
}
/// <summary>
/// Started the transaction implicitly.
/// </summary>
private static int TestOnImplicitlyStartedTransaction()
{
var affectedRows = 0;
var customerId = "RATTC";
var employeeId = 6;
var invalidEmployeeId = int.MaxValue;
using (var dbContext = new NorthwindEntities())
{
try
{
#region [Add Orders]
// This cause an error
var firstOrder = new Order()
{
CustomerID = customerId,
EmployeeID = invalidEmployeeId // employeeId
};
dbContext.Orders.Add(firstOrder);
var secondOrder = new Order()
{
CustomerID = customerId,
EmployeeID = employeeId
};
secondOrder.Order_Details.Add(new Order_Detail()
{
OrderID = secondOrder.OrderID,
ProductID = 5,
UnitPrice = 12.34m,
Quantity = 100,
Discount = 0.2f
});
dbContext.Orders.Add(secondOrder);
#endregion
affectedRows = dbContext.SaveChanges();
Console.WriteLine("- Finish successfully => Commit transaction");
}
catch (Exception)
{
Console.WriteLine("- Exception: Finish Unsuccessfully => Rollback transaction");
}
}
return affectedRows;
}
