private void JoiningTableData_Load(object sender, EventArgs e)
{
BooksExamples.BooksEntities dbcontext = new BooksExamples.BooksEntities();
var authorAndISBNs =
from author in dbcontext.Authors
from book in author.Titles
orderby author.LastName, author.FirstName
select new {author.FirstName, author.LastName, book.ISBN};
outputTextBox.AppendText("Authors and ISBNs");
foreach (var record in authorAndISBNs)
{
outputTextBox.AppendText(
String.Format("\r\n\t{0,-10} {1,-10} {2,-10}", record.FirstName, record.LastName,record.ISBN));
}
var authorsAndTitles =
from book in dbcontext.Titles
from author in dbcontext.Authors
orderby author.LastName, author.FirstName, book.Title1
select new {author.FirstName, author.LastName, book.Title1};
outputTextBox.AppendText("\r\n\r\nAuthors and titles:");
foreach (var record in authorsAndTitles)
{
outputTextBox.AppendText(
String.Format("\r\n\t{0,-10} {1,-10} {2,-10}", record.FirstName, record.LastName,record.Title1));
}
}
private void JoiningTableData_Load(object sender, EventArgs e)
{
// Entity Framework DbContext
var dbcontext = new BooksExamples.BooksEntities();
// get authors and ISBNs of each book they co-authored
var authorsAndISBNs =
from author in dbcontext.Authors
from title in author.Titles
orderby author.LastName, author.FirstName
select new { author.FirstName, author.LastName, title.ISBN };
var authorsAndISBNsMethodSyntax = dbcontext
.Authors
.SelectMany(a => a.Titles,
(author, title) => new { author, title = title })
.OrderBy(t => t.author.LastName)
.ThenBy(t => t.author.FirstName)
.Select(t => new { t.author.FirstName, t.author.LastName, t.title.ISBN });
outputTextBox.AppendText("Authors and ISBNs:");
// display authors and ISBNs in tabular format
foreach (var element in authorsAndISBNsMethodSyntax)
{
outputTextBox.AppendText($"\r\n\t{element.FirstName,-10} " +
$"{element.LastName,-10} {element.ISBN,-10}");
}
// get authors and titles of each book they co-authored
var authorsAndTitles =
from book in dbcontext.Titles
from author in book.Authors
orderby author.LastName, author.FirstName, book.Title1
select new { author.FirstName, author.LastName, book.Title1 };
var authorsAndTitlesMethodSyntax = dbcontext
.Titles
.SelectMany(book => book.Authors,
(book, author) => new { book, author })
.OrderBy(t => t.author.LastName)
.ThenBy(t => t.author.FirstName)
.ThenBy(t => t.book.Title1)
.Select(t => new { t.author.FirstName, t.author.LastName, t.book.Title1 });
outputTextBox.AppendText("\r\n\r\nAuthors and titles:");
// display authors and titles in tabular format
foreach (var element in authorsAndTitles)
{
outputTextBox.AppendText($"\r\n\t{element.FirstName,-10} " +
$"{element.LastName,-10} {element.Title1}");
}
// get authors and titles of each book
// they co-authored; group by author
var titlesByAuthor =
from author in dbcontext.Authors
orderby author.LastName, author.FirstName
select new { Name = author.FirstName + " " + author.LastName,
Titles =
from book in author.Titles
orderby book.Title1
select book.Title1 };
outputTextBox.AppendText("\r\n\r\nTitles grouped by author:");
// display titles written by each author, grouped by author
foreach (var author in titlesByAuthor)
{
// display author's name
outputTextBox.AppendText($"\r\n\t{author.Name}:");
// display titles written by that author
foreach (var title in author.Titles)
{
outputTextBox.AppendText($"\r\n\t\t{title}");
}
}
}
