private static void DynamicLinq(EntitiesModel context)
{
// strongly typed dynamic LINQ
Console.WriteLine("Dynamic strongly typed LINQ Where:");
var query1 = context.Cars.Where("CarYear < @0", 2000).ToList();
Console.WriteLine("Car\tCategory");
foreach (var car in query1)
{
Console.WriteLine("{0}\t{1}", car.CarID, car.Category.CategoryName);
}
// weakly typed dynamic LINQ with projection
Console.WriteLine("Dynamic weakly typed LINQ Where and Select:");
var objList = context.GetAll("OpenAccessModel9.Car").Where("CarYear < @0", 2000)
.Select("new (CarID as Id, CarYear)")
.Cast<object>().ToList();
foreach (object objCar in objList)
{
Console.WriteLine(objCar);
}
}
private static void BulkDelete(EntitiesModel context)
{
// avoid showing the INSERT statements that populate the data
context.Log = null;
for (int i = 0; i < 10; i++)
{
Car car = new Car() { Make = "BMW", Model = "1020", CarYear = 2018, Available = true, CategoryID = 1, TagNumber = i.ToString()};
context.Add(car);
}
context.SaveChanges();
// show the delete statements
context.Log = Console.Out;
var query = context.GetAll<Car>().Where(c => c.CarYear > DateTime.Now.Year);
int deleted = query.DeleteAll();
Console.WriteLine("Deleted cars: {0}", deleted);
}
private static void BulkUpdate(EntitiesModel context)
{
string tooOldName = "Too old";
Category tooOldCategory = context.Categories.FirstOrDefault(c => c.CategoryName == tooOldName);
if (tooOldCategory == null)
{
tooOldCategory = new Category();
tooOldCategory.CategoryName = tooOldName;
context.Add(tooOldCategory);
context.SaveChanges();
}
var query = context.GetAll<Car>().Where(c => c.CarYear < 2000);
int updated = query.UpdateAll(u => u.Set(c => c.Category, c => tooOldCategory)
.Set(c => c.Available, c => false));
Console.WriteLine("Updated cars: {0}", updated);
}
