public static void DisplayAuthorsWithAtLeastABookPriceLowerThan(double bookPrice)
{
using (var context = new BookLibraryDbContext())
{
var authorsWithBookPriceGreaterThan = context.Authors
.Where(a => a.Books.Any(b => b.Price > bookPrice));
foreach (var item in authorsWithBookPriceGreaterThan)
{
Console.WriteLine($"For {item.Name} there is at least a book with price lower than: {bookPrice}");
}
}
}
public static void DisplayAuthorsWithAllBookPricesGreaterThan(double bookPrice)
{
using (var context = new BookLibraryDbContext())
{
var authorsWithBookPriceGreaterThan = context.Authors
.Where(a => a.Books.All(b => b.Price > bookPrice));
foreach (var item in authorsWithBookPriceGreaterThan)
{
Console.WriteLine($"For {item.Name} all books have prices greater than: {bookPrice}");
}
}
}
public static void DisplayAuthorsWithAverageBookPrice()
{
using (var context = new BookLibraryDbContext())
{
var authorsWithAverageBookPrice = context.Authors
.Select(a => new
{
Author = a.Name,
AveragePrice = a.Books.Average(b => b.Price)
});
foreach (var item in authorsWithAverageBookPrice)
{
Console.WriteLine($"{item.Author}, {item.AveragePrice} EUR");
}
}
}
public static void DisplayAuthorsWithBooksAndPublishers()
{
using (var context = new BookLibraryDbContext())
{
var authorWithBookAndPublisher = context.Authors
.SelectMany(a => a.Books, (a, b) => new
{
Author = a.Name,
Book = b.Title,
Publisher = b.Publisher
});
foreach (var item in authorWithBookAndPublisher)
{
Console.WriteLine($"{item.Author}, {item.Book}, {item.Publisher}");
}
}
}
public static void DisplayNumberOfBooksForEachPublisher()
{
using (var context = new BookLibraryDbContext())
{
var groupByPublisher = context.Books
.GroupBy(b => b.Publisher)
.Select(b => new
{
Publisher = b.Key,
NumberOfBooks = b.Count()
});
foreach (var item in groupByPublisher)
{
Console.WriteLine($"{item.Publisher}: {item.NumberOfBooks} books");
}
}
}
public static void DisplayPublishersWithMoreThanNumberOfBooks(int numberOfBooks)
{
using (var context = new BookLibraryDbContext())
{
var groupByPublisher = context.Books
.GroupBy(b => b.Publisher)
.Select(b => new
{
Publisher = b.Key,
NumberOfBooks = b.Count()
})
.Where(p => p.NumberOfBooks > numberOfBooks);
foreach (var item in groupByPublisher)
{
Console.WriteLine($"{item.Publisher}: {item.NumberOfBooks} books");
}
}
}
public static void DisplayBooksOnCategories()
{
using (var context = new BookLibraryDbContext())
{
var categorizeBooks = context
.Books
.Select(b => new
{
Title = b.Title,
Category = b.Price >= 80 ?
"Expensive" : "Affordable"
});
foreach (var item in categorizeBooks)
{
Console.WriteLine($"Book {item.Title}: {item.Category} category");
}
}
}
