/// <summary>
/// 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.
/// </summary>
private static void AddOrder()
{
var databaseConnection = new NorthwindEntities();
using (databaseConnection)
{
using (var dbContextTransaction = databaseConnection.Database.BeginTransaction())
{
try
{
var newOrder = new Order()
{
CustomerID = "BOTTM",
EmployeeID = 5,
OrderDate = DateTime.Now
};
newOrder.Order_Details.Add(new Order_Detail { ProductID = 11, UnitPrice = 14.00m, Quantity = 12, Discount = 0 });
newOrder.Order_Details.Add(new Order_Detail { ProductID = 42, UnitPrice = 9.80m, Quantity = 5, Discount = 0 });
newOrder.Order_Details.Add(new Order_Detail { ProductID = 72, UnitPrice = 34.50m, Quantity = 7, Discount = 0 });
databaseConnection.Orders.Add(newOrder);
databaseConnection.SaveChanges();
dbContextTransaction.Commit();
}
catch (Exception)
{
dbContextTransaction.Rollback();
}
}
}
}
public static void UpdateCustomer(string customerToEditID, string newName)
{
var databaseConnection = new NorthwindEntities();
using (databaseConnection)
{
var customer = databaseConnection.Customers.FirstOrDefault(c => c.CustomerID == customerToEditID);
customer.ContactName = newName;
databaseConnection.SaveChanges();
}
}
public static void DeleteCustomer(string customerToEditID)
{
var databaseConnection = new NorthwindEntities();
using (databaseConnection)
{
var customer = databaseConnection.Customers.FirstOrDefault(c => c.CustomerID == customerToEditID);
if (customer != null)
{
databaseConnection.Customers.Remove(customer);
databaseConnection.SaveChanges();
}
}
}
public static void InsertCustomer(string customerID, string companyName, string contactName, string contactTitle)
{
var databaseConnection = new NorthwindEntities();
var newCustomer = new Customer
{
CustomerID = customerID,
CompanyName = companyName,
ContactName = contactName,
ContactTitle = contactTitle
};
using (databaseConnection)
{
databaseConnection.Customers.Add(newCustomer);
databaseConnection.SaveChanges();
}
}
