/*********************************************************
#A This method gets a PriceOffer class to send to the user to update
#B This loads the book with any existing Promotion
#C I return either the existing Promotion for editing, or create a new one. The important point is to set the BookId, as we need to pass that through to the second stage
* ******************************************************/
/// <summary>
/// This deletes a promotion if the book has one, otherwise is adds a promotion
/// </summary>
/// <param name="promotion"></param>
/// <returns></returns>
public ValidationResult AddRemovePriceOffer(PriceOffer promotion) //#A
{
var book = _context.Books //#B
.Include(r => r.Promotion) //#B
.Single(k => k.BookId //#B
== promotion.BookId); //#B
if (book.Promotion != null) //#C
{
_context.Remove(book.Promotion); //#D
_context.SaveChanges(); //#D
return(null); //#E
}
if (string.IsNullOrEmpty(promotion.PromotionalText)) //#F
{
return(new ValidationResult( //#G
"This field cannot be empty", //#G
new [] { nameof(PriceOffer.PromotionalText) })); //#G
}
book.Promotion = promotion; //#H
_context.SaveChanges(); //#I
return(null); //#J
}
public void TestDeletePriceOffer()
{
//SETUP
var options = SqliteInMemory.CreateOptions <EfCoreContext>();
using (var context = new EfCoreContext(options))
{
context.Database.EnsureCreated();
context.SeedDatabaseFourBooks();
var numPromotions = context.PriceOffers.Count();
//ATTEMPT
var promotion = context.PriceOffers //#A
.First(); //#A
context.Remove(promotion); //#B
context.SaveChanges(); //#C
/**********************************************************
#A I find the first PriceOffer
#B I then remove that PriceOffer from the application's DbContext. The DbContext works what to remove based on its type of its parameter
#C The SaveChanges calls DetectChanges which finds a tracked PriceOffer entity which is marked as deleted. It then deletes it from the database
* *******************************************************/
//VERIFY
context.PriceOffers.Count().ShouldEqual(numPromotions - 1);
}
}
public void TestDeletePriceOffer()
{
//SETUP
var options = SqliteInMemory.CreateOptions <EfCoreContext>();
using (var context = new EfCoreContext(options))
{
context.Database.EnsureCreated();
context.SeedDatabaseFourBooks();
var book = context.Books
.First(p => p.Promotion != null);
//ATTEMPT
context.Remove(context.PriceOffers.Find(book.Promotion.PriceOfferId));
context.SaveChanges();
//VERIFY
var bookAgain = context.Books
.Include(p => p.Promotion)
.Single(p => p.BookId == book.BookId);
bookAgain.Promotion.ShouldBeNull();
context.PriceOffers.Count().ShouldEqual(0);
}
}
public void TestRemoveLinkByDeleteToAuthorOk()
{
//SETUP
var options = SqliteInMemory.CreateOptions <EfCoreContext>();
using var context = new EfCoreContext(options);
context.Database.EnsureCreated();
context.SeedDatabaseDummyBooks(1);
var bookId = context.Books.First().BookId;
context.ChangeTracker.Clear();
//ATTEMPT
var existingBook = context.Books
.Include(book => book.AuthorsLink.OrderBy(x => x.Order))
.Single(book => book.BookId == bookId);
var linkToRemove = existingBook.AuthorsLink.Last();
context.Remove(linkToRemove);
context.SaveChanges();
context.ChangeTracker.Clear();
//VERIFY
var bookAgain = context.Books
.Include(p => p.AuthorsLink).ThenInclude(p => p.Author)
.Single(p => p.BookId == bookId);
bookAgain.AuthorsLink.ShouldNotBeNull();
bookAgain.AuthorsLink.Count.ShouldEqual(1);
bookAgain.AuthorsLink.First().Author.Name.ShouldEqual("Author0000");
}
public void Delete(int id)
{
using (var context = new EfCoreContext())
{
try
{
var result = context.Players.Where(p => p.Identity.Id == id).SingleOrDefault();
context.Remove(result);
context.SaveChanges();
}
catch (NullReferenceException e)
{
throw new ArgumentException(e.Message + $" Player with {id} was not found");
}
}
}
public void TestDeleteBookMissing()
{
//SETUP
var options = SqliteInMemory.CreateOptions <EfCoreContext>();
using var context = new EfCoreContext(options);
context.Database.EnsureCreated();
//ATTEMPT
var book = new Book
{
BookId = 123
};
context.Remove(book);
var ex = Assert.Throws <DbUpdateConcurrencyException>(() => context.SaveChanges());
//VERIFY
ex.Message.ShouldStartWith("Database operation expected to affect 1 row(s) but actually affected 0 row(s).");
}
public void TestDeleteBookWithDependentEntityCascadeDeleteOk()
{
//SETUP
int bookId;
var options = SqliteInMemory.CreateOptions <EfCoreContext>();
using var context = new EfCoreContext(options);
context.Database.EnsureCreated();
var bookSetup = new Book
{
Title = "Test Book",
Reviews = new List <Review> {
new Review()
}
};
context.Add(bookSetup);
context.SaveChanges();
bookId = bookSetup.BookId;
context.Books.Count().ShouldEqual(1);
context.Set <Review>().Count().ShouldEqual(1);
context.ChangeTracker.Clear();
//ATTEMPT
var book = new Book {
BookId = bookId
};
context.Remove(book);
context.SaveChanges();
context.ChangeTracker.Clear();
//VERIFY
context.ChangeTracker.Clear();
context.Books.Count().ShouldEqual(0);
context.Set <Review>().Count().ShouldEqual(0);
}
public void TestDeleteBookNoRelationshipsOk()
{
//SETUP
int bookId;
var options = SqliteInMemory.CreateOptions <EfCoreContext>();
using var context = new EfCoreContext(options);
context.Database.EnsureCreated();
var bookSetup = new Book {
Title = "Test Book"
};
context.Add(bookSetup);
context.SaveChanges();
bookId = bookSetup.BookId;
context.ChangeTracker.Clear();
//ATTEMPT
var book = new Book //#A
{
BookId = bookId //#B
};
context.Remove(book); //#C
context.SaveChanges(); //#D
/*****************************************************
#A This creates the entity class that we want to delete - in this case a Book
#B This sets the primary key of the entity instance
#C The call to Remove tells EF Core you want this entity/row to be deleted
#D Then SaveChanges sends the command to the database to delete that row
****************************************************/
context.ChangeTracker.Clear();
//VERIFY
context.Books.Count().ShouldEqual(0);
}
public void TestDeletePriceOfferQuicklyOk()
{
//SETUP
int priceOfferId;
var options = SqliteInMemory.CreateOptions <EfCoreContext>();
using var context = new EfCoreContext(options);
context.Database.EnsureCreated();
var book = new Book
{
Title = "Test Book",
Promotion = new PriceOffer {
NewPrice = 1
}
};
context.Add(book);
context.SaveChanges();
priceOfferId = book.Promotion.PriceOfferId;
context.Books.Count().ShouldEqual(1);
context.PriceOffers.Count().ShouldEqual(1);
context.ChangeTracker.Clear();
//ATTEMPT
var pOfferToDelete = new PriceOffer {
PriceOfferId = priceOfferId
};
context.Remove(pOfferToDelete);
context.SaveChanges();
context.ChangeTracker.Clear();
//VERIFY
context.Books.Count().ShouldEqual(1);
context.PriceOffers.Count().ShouldEqual(0);
}
public void TestLoadOnlyBookAndDelete()
{
//SETUP
var options = SqliteInMemory.CreateOptions <EfCoreContext>();
using var context = new EfCoreContext(options);
context.Database.EnsureCreated();
context.SeedDatabaseFourBooks();
context.ChangeTracker.Clear();
//ATTEMPT
var book = context.Books
.Single(p => p.Title == "Quantum Networking");
context.Remove(book);
context.SaveChanges();
//VERIFY
context.Books.Count().ShouldEqual(3);
context.Set <BookAuthor>().Count().ShouldEqual(3);
context.Set <Review>().Count().ShouldEqual(0);
}
public void TestDeletePriceOfferRemoveNullsNavigatinalLinkOk()
{
//SETUP
var options = SqliteInMemory.CreateOptions <EfCoreContext>();
using var context = new EfCoreContext(options);
context.Database.EnsureCreated();
var book = new Book
{
Title = "Test Book",
Promotion = new PriceOffer {
NewPrice = 1
}
};
context.Add(book);
context.SaveChanges();
context.Books.Count().ShouldEqual(1);
context.PriceOffers.Count().ShouldEqual(1);
context.ChangeTracker.Clear();
//ATTEMPT
var bookWithPromotion = context.Books
.Include(x => x.Promotion).Single();
context.Remove(bookWithPromotion.Promotion);
context.SaveChanges();
bookWithPromotion.Promotion.ShouldBeNull();
context.ChangeTracker.Clear();
//VERIFY
context.Books.Count().ShouldEqual(1);
context.PriceOffers.Count().ShouldEqual(0);
}
