//2.Create a DAO class with static methods which provide functionality for inserting,
// modifying and deleting customers. Write a testing class
public void InsertCustomer(
string companyName,
string contactName,
string contactTitle,
string address,
string city,
string region,
string postalCode,
string country,
string phone,
string fax)
{
var db = new NORTHWNDEntities();
using (db)
{
Customer myCustomer = new Customer();
myCustomer.Address = address;
myCustomer.City = city;
myCustomer.CompanyName = companyName;
myCustomer.ContactName = contactName;
myCustomer.ContactTitle = contactTitle;
myCustomer.Country = country;
myCustomer.Fax = fax;
myCustomer.Phone = phone;
myCustomer.Region = region;
myCustomer.PostalCode = postalCode;
string cusId = contactName.Substring(0, 5);
myCustomer.CustomerID = cusId;
db.Customers.Add(myCustomer);
db.SaveChanges();
}
}
public void UpdateCustomer(
string oldName,
string companyName,
string contactName,
string contactTitle,
string address,
string city,
string region,
string postalCode,
string country,
string phone,
string fax)
{
var db = new NORTHWNDEntities();
using (db)
{
var customer = db.Customers.Where(x => x.CompanyName == oldName).First();
customer.Address = address;
customer.City = city;
customer.CompanyName = companyName;
customer.ContactName = contactName;
customer.ContactTitle = contactTitle;
customer.Country = country;
customer.Fax = fax;
customer.Phone = phone;
customer.Region = region;
customer.PostalCode = postalCode;
string cusId = contactName.Substring(0, 5);
customer.CustomerID = cusId;
db.SaveChanges();
}
}
public void DeleteCustomer(string customerName)
{
var db = new NORTHWNDEntities();
using (db)
{
var customer = db.Customers.Where(x => x.CompanyName == customerName).First();
db.Customers.Remove(customer);
db.SaveChanges();
}
}
public void FindCustomer(string customerName)
{
var db = new NORTHWNDEntities();
using (db)
{
var customer = db.Customers.Where(x => x.CompanyName == customerName).First();
Console.WriteLine(customer.CompanyName);
}
}
//10.Create a stored procedures in the Northwind database for finding the total incomes for
//given supplier name and period (start date, end date). Implement a C# method that calls
//the stored procedure and returns the retuned record set.
public void CalculateIncoms(string supplierName, DateTime minDate, DateTime maxDate)
{
var db = new NORTHWNDEntities();
using (db)
{
//Execute first USP.sql
var result = db.usp_FindTotalIncome(minDate.Year, maxDate.Year, supplierName);
Console.WriteLine(result.FirstOrDefault());
}
}
//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.
public void MakeOrder(Order myOrder, List<Tuple<int, int, int>> items)
{
var db = new NORTHWNDEntities();
using (db)
{
using(TransactionScope scope = new TransactionScope())
{
var newOrder = db.Orders.Add(myOrder);
foreach (var item in items)
{
Order_Detail myDetail = new Order_Detail
{
OrderID = newOrder.OrderID,
ProductID = item.Item1,
Quantity = (short)item.Item2,
UnitPrice = (short)item.Item3
};
db.Order_Details.Add(myDetail);
}
try
{
db.SaveChanges();
scope.Complete();
Console.WriteLine("OK");
}
catch (Exception)
{
Console.WriteLine("Rollback!!");
scope.Dispose();
}
}
}
}
//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?
public void CheckConcurrent()
{
var db = new NORTHWNDEntities();
var db2 = new NORTHWNDEntities();
var region = db.Regions.Find(5);
region.RegionDescription = "Burgas";
db.SaveChanges();
Console.WriteLine("Updated");
var region2 = db.Regions.Find(5);
db2.Regions.Remove(region2);
db2.SaveChanges();
Console.WriteLine("Deleted");
}
//5.Write a method that finds all the sales by specified region and period (start / end dates).
public void FindSales(string region, DateTime minDate, DateTime maxDate)
{
var db = new NORTHWNDEntities();
using (db)
{
var sales = db.Orders.Where(x => x.ShipRegion == region).
Where(x => x.ShippedDate > minDate).
Where(x => x.ShippedDate < maxDate);
foreach (var sale in sales)
{
Console.WriteLine(sale.ShippedDate + " " + sale.ShipRegion);
}
}
}
//4.Implement previous by using native SQL query and executing it through the DbContext.
public void FindCustomerByYearSql()
{
var db = new NORTHWNDEntities();
using (db)
{
string query = @"SELECT DISTINCT CompanyName FROM Customers c
JOIN Orders o
ON o.CustomerID = c.CustomerID
WHERE o.ShipCountry = 'Canada' AND YEAR(o.OrderDate) = '1997'";
var queryResult = db.Database.SqlQuery<string>(query);
foreach (var res in queryResult)
{
Console.WriteLine(res);
}
}
}
//3.Write a method that finds all customers who have orders made in 1997 and shipped to Canada
public void FindCustomerByYear()
{
var db = new NORTHWNDEntities();
using (db)
{
DateTime time = new DateTime(1997, 1, 1);
var customers = db.Orders.Where(x => x.OrderDate.Value.Year == time.Year).Where(x => x.ShipCountry == "Canada");
foreach (var customer in customers.Distinct())
{
Console.WriteLine(customer.Customer.CompanyName);
}
}
}
