Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>You don't need to do anything special. Classes are always nullable.</p> <p>I just tried this (with MVC3):</p> <p>In my Models directory:</p> <pre><code>namespace MvcApplication2.Models { public class Book { public int ID { get; set; } public string Title { get; set; } public string Author { get; set; } public string ISBN { get; set; } public virtual Loaner LoanedTo { get; set; } } public class Loaner { public int ID { get; set; } public string Name { get; set; } public virtual ICollection&lt;Book&gt; Loans { get; set; } } public class BookContext : System.Data.Entity.DbContext { public System.Data.Entity.DbSet&lt;Book&gt; Books { get; set; } public System.Data.Entity.DbSet&lt;Loaner&gt; Loaners { get; set; } } } </code></pre> <p>In my HomeController:</p> <pre><code>namespace MvcApplication2.Controllers { public class HomeController : Controller { // // GET: /Home/ public ActionResult Index() { string message = "OK"; try { var context = new Models.BookContext(); var book = new Models.Book(); book.Title = "New Title"; book.Author = "New Author"; book.ISBN = "New ISBN"; context.Books.Add(book); context.SaveChanges(); } catch (Exception err) { message = err.ToString(); } ViewBag.Message = message; return View(); } } } </code></pre> <p>The connectionstring in Web.Config:</p> <pre><code>&lt;add name="BookContext" connectionString="Data Source=|DataDirectory|BookContext.sdf" providerName="System.Data.SqlServerCe.4.0" /&gt; </code></pre> <p>When I run the application, the view displays "OK". This means that no exception was thrown. When I look in my App_Data folder, a BookContext.sdf file has been created. That database contains a table for the Books and the Loaners. The table for the Loaners is empty. The one for the Books contains one record:</p> <pre><code>ID: 1; Title: "New Title"; Author: "New Author"; ISBN: "New ISBN"; LoanerID: null </code></pre>
    singulars
    1. This table or related slice is empty.
    1. POHow to make a nullable property in EF Codefirst?
      singulars
      1. PTQuestion
    1. PTAnswer
    1. This table or related slice is empty.
    1. USKristof Claes
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. POHow to make a nullable property in EF Codefirst?
      singulars
      1. PTQuestion
    1. This table or related slice is empty.
    1. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTAcceptedByOriginator
    2. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    3. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    1. COWow, I guess I should have tested my db and classes before moving to the next step. Turns out you're right. Something further down my app is wrong. Thanks
      singulars
      1. PO
      1. USNiclas Lindqvist
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload