Code-First
- Microsoft.EntityFrameworkCore.Tools
- Microsoft.EntityFrameworkCore.Design
- Microsoft.EntityFrameworkCore.Sqlite
- AuthorId: Sie gibt an, welcher Author das Buch geschrieben hat.
- Author-Objekt: Hierbei ist wichtig, dass du als Datentyp Author, also das Author-Modell nimmst und das Keyword "virtual" davor schreibst.
public class Author
{
public int Id { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
public DateTime Birthday { get; set; }
}
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public class Book
{
public int Id { get; set; }
public string Title { get; set; }
public int AuthorId { get; set; }
public virtual Author Author { get; set; }
}
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Erstellen des Datenbank-Context
public class DatabaseContext : DbContext
{
public DbSet<Author> Authors { get; set; }
public DbSet<Book> Books { get; set; }
protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
{
var folder = Environment.SpecialFolder.LocalApplicationData;
var path = Environment.GetFolderPath(folder);
var DbPath = $"{path}{Path.DirectorySeparatorChar}ef-tutorial.db";
optionsBuilder.UseSqlite($"Data Source={DbPath}");
}
}
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Datenbank erstellen
Zugriff auf die Datenbank im Code
static void Main(string[] args)
{
using (var db = new DatabaseContext())
{
var jkRowling = new Author
{
FirstName = "Joanne",
LastName = "Rowling",
Birthday = new DateTime(1965, 7, 31)
};
db.Authors.Add(jkRowling);
db.Books.Add(new Book
{
Title = "Harry Potter and the Philosopher's Stone",
Author = jkRowling
});
db.SaveChanges();
}
}
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var jkRowling = db.Authors.Include(a => a.Books).First(author => author.FirstName == "Joanne");
foreach (var book in jkRowling.Books)
{
Console.WriteLine(book.Title);
}
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