public static void Insert(string customerId, string companyName, string address = null,
string city = null, string contactName = null, string contactTitle = null, string country = null,
string fax = null, string phone = null, string postalCode = null, string region = null)
{
using (NorthwindEntities dbContext = new NorthwindEntities())
{
Customer newCustomer = new Customer()
{
Address = address,
City = city,
CompanyName = companyName,
ContactName = contactName,
ContactTitle = contactTitle,
Country = country,
CustomerID = customerId,
Fax = fax,
Phone = phone,
PostalCode = postalCode,
Region = region
};
dbContext.Customers.Add(newCustomer);
dbContext.SaveChanges();
}
}
public static int AddCustomer(Customer newCustomer)
{
using (var dataBase = new NorthwindEntities())
{
dataBase.Customers.Add(newCustomer);
return dataBase.SaveChanges();
}
}
/// <summary>
/// Adds a customer to customers table.
/// </summary>
/// <param name="customer">The customer to be added.</param>
public static void AddCustomer(Customer customer)
{
using (var northwindDbContext = new NorthwindEntities())
{
northwindDbContext.Customers.Add(customer);
northwindDbContext.SaveChanges();
Console.WriteLine("Customer successfully added!");
}
}
public static int DeleteCustomer(string id)
{
using (var dataBase = new NorthwindEntities())
{
Customer customer = dataBase.Customers.First(x => x.CustomerID == id);
dataBase.Customers.Remove(customer);
return dataBase.SaveChanges();
}
}
//2. Create a DAO class with static methods which provide functionality
//for inserting, modifying and deleting customers. Write a testing class.
public static void Delete(string customerId)
{
using (NorthwindEntities dbContext = new NorthwindEntities())
{
Customer customer = dbContext.Customers.Find(customerId);
dbContext.Customers.Remove(customer);
dbContext.SaveChanges();
}
}
public static int UpdateContactNameTitle(Customer customer, string contactName, string contactTitle)
{
using (var northwindEntities = new NorthwindEntities())
{
northwindEntities.Customers.Attach(customer);
customer.CompanyName = contactName;
customer.ContactTitle = contactTitle;
return northwindEntities.SaveChanges();
}
}
/* 02. Create a DAO class with static methods which provide functionality for inserting, modifying and deleting customers. Write a testing class.*/
/// <summary>
/// Deletes a customer identified by CustomerID.
/// </summary>
/// <param name="customer">The customer.</param>
public static void DeleteCustomer(Customer customer)
{
using (var northwindDbContext = new NorthwindEntities())
{
var customerForDelete = northwindDbContext.Customers.First(c => c.CustomerID == customer.CustomerID);
northwindDbContext.Customers.Remove(customerForDelete);
northwindDbContext.SaveChanges();
Console.WriteLine("Customer successfully deleted!");
}
}
public static void Modify(string customerId, string companyName /*= null, string address = null,
string city = null, string contactName = null, string contactTitle = null, string country = null,
string fax = null, string phone = null, string postalCode = null, string region = null*/)
{
using (NorthwindEntities dbContext = new NorthwindEntities())
{
Customer customer = dbContext.Customers.Find(customerId);
customer.CompanyName = companyName;
dbContext.SaveChanges();
}
}
/* 07. Try to open two different data contexts and perform concurrent changes on the same records. What will happen at SaveChanges()? How to deal with it?*/
// EF executes everything in transactions by default. We don`t need to worry about it.
/// <summary>
/// Mains this instance.
/// </summary>
public static void Main()
{
using (var northwindDbContext = new NorthwindEntities())
{
using (var secondNorthwindDbContext = new NorthwindEntities())
{
var order = northwindDbContext.Orders.Find(10248);
var sameOrder = secondNorthwindDbContext.Orders.Find(10248);
// Mark for delete
northwindDbContext.Orders.Remove(order);
// Update some stuff
sameOrder.ShipCountry = "Bulgaria";
// Make update
try
{
secondNorthwindDbContext.SaveChanges();
Console.WriteLine("Updating complete!");
}
catch (Exception)
{
Console.WriteLine("Updating failed!");
}
// Delete -> Produces an exception because of data integrity.
try
{
northwindDbContext.SaveChanges();
Console.WriteLine("Deleting complete!");
}
catch (Exception)
{
Console.WriteLine("Delete cannot be executed!");
}
}
}
Console.WriteLine("Done!");
}
public static int AddOrder(Order newOrder)
{
using (var dataBase = new NorthwindEntities())
{
var customer = dataBase.Customers.First(c => c.CustomerID == newOrder.CustomerID);
if (customer != null)
{
newOrder.ShipAddress = customer.Address;
newOrder.ShipCity = customer.City;
newOrder.ShipPostalCode = customer.PostalCode;
newOrder.ShipCountry = customer.Country;
}
dataBase.Orders.Add(newOrder);
dataBase.Orders.Add(newOrder);
dataBase.Orders.Add(newOrder);
return dataBase.SaveChanges();
}
}
/// <summary>
/// Adds an order multiple times to the db. Transaction demo.
/// </summary>
/// <param name="order">The order.</param>
private static void AddOrderMultipleTimes(Order order)
{
using (var northwindDbContext = new NorthwindEntities())
{
northwindDbContext.Orders.Add(order);
northwindDbContext.Orders.Add(order);
northwindDbContext.Orders.Add(order);
//// Uncomment to see transaction power!
// order.CustomerID = "PESHO_ZLIA";
northwindDbContext.Orders.Add(order);
northwindDbContext.Orders.Add(order);
try
{
northwindDbContext.SaveChanges();
}
catch (Exception)
{
Console.WriteLine("Error! Orders not confirmed!");
}
}
}
private static void PlaceNewOrder(
int orderId, string customerId = null,
int? employeeId = null, DateTime? orderDate = null,
DateTime? requireDate = null, DateTime? shippedDate = null,
int? shipVia = null, decimal? freight = null,
string shipName = null, string shipAddress = null,
string shipCity = null, string shipRegion = null,
string shipPostalCode = null, string shipCountry = null)
{
//9. Create a method that places a new order in the Northwind database. The order
//should contain several order items. Use transaction to ensure the data consistency.
using (NorthwindEntities dbContext = new NorthwindEntities())
{
Order newOrder = new Order()
{
CustomerID = customerId,
EmployeeID = employeeId,
Freight = freight,
OrderDate = orderDate,
OrderID = orderId,
RequiredDate = requireDate,
ShipAddress = shipAddress,
ShipCity = shipCity,
ShipCountry = shipCountry,
ShipName = shipName,
ShippedDate = shippedDate,
ShipPostalCode = shipPostalCode,
ShipRegion = shipRegion,
ShipVia = shipVia,
};
dbContext.Orders.Add(newOrder);
dbContext.SaveChanges();
}
}
private static void MakeConcurencyChanges()
{
//7. Try to open two different data contexts and perform concurrent changes
//on the same records. What will happen at SaveChanges()? How to deal with it?
NorthwindEntities dbContext1 = new NorthwindEntities();
Employee employee1 = dbContext1.Employees.Find(10);
//employee1.City = "Burgas";
dbContext1.Employees.Remove(employee1);
//dbContext1.SaveChanges();
NorthwindEntities dbContext2 = new NorthwindEntities();
Employee employee2 = dbContext2.Employees.Find(10);
employee2.City = "Varna";
dbContext1.SaveChanges();
dbContext2.SaveChanges();
dbContext1.Dispose();
dbContext2.Dispose();
}
/// <summary>
/// Updates a customer identified by CustomerID.
/// </summary>
/// <param name="customer">The customer.</param>
public static void UpdateCustomer(Customer customer)
{
using (var northwindDbContext = new NorthwindEntities())
{
var customerForUpdate = northwindDbContext.Customers.First(c => c.CustomerID == customer.CustomerID);
customerForUpdate.CompanyName = customer.CompanyName ?? customerForUpdate.CompanyName;
customerForUpdate.ContactName = customer.ContactName ?? customerForUpdate.ContactName;
customerForUpdate.ContactTitle = customer.ContactTitle ?? customerForUpdate.ContactTitle;
customerForUpdate.Address = customer.Address ?? customerForUpdate.Address;
customerForUpdate.City = customer.City ?? customerForUpdate.City;
customerForUpdate.Region = customer.Region ?? customerForUpdate.Region;
customerForUpdate.PostalCode = customer.PostalCode ?? customerForUpdate.PostalCode;
customerForUpdate.Country = customer.Country ?? customerForUpdate.Country;
customerForUpdate.Phone = customer.Phone ?? customerForUpdate.Phone;
customerForUpdate.Fax = customer.Fax ?? customerForUpdate.Fax;
northwindDbContext.SaveChanges();
Console.WriteLine("The customer is Updated!");
}
}
