Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>I don't know if the following is a solution for you but Entity Framework supports <a href="https://stackoverflow.com/a/762994/270591">Identifying Relationships</a>. In such a relationship the foreign key of the child entity (dependent) to the parent (principal) must be part of the (composite) primary key of the child entity. For example - with <code>DbContext</code> data annotations - your model classes have to look like this:</p> <pre><code>public class Order { [Key] public int OrderId { get; set; } public ICollection&lt;OrderLine&gt; OrderLines { get; set; } } public class OrderLine { [Key, ForeignKey("Order"), Column(Order = 1)] public int OrderId { get; set; } [Key, Column(Order = 2)] public int OrderLineId { get; set; } public Order Order { get; set; } } </code></pre> <p>You can make the <code>OrderLineId</code> an autogenerated identity if you want. Important is only that the FK to <code>Order</code> is part of the PK.</p> <p>A code like this for example...</p> <pre><code>using (var ctx = new MyContext()) { var order = ctx.Orders.Include("OrderLines").Single(o =&gt; o.OrderId == 1); var orderLineToDelete = order.OrderLines .FirstOrDefault(ol =&gt; ol.OrderLineId == 5); if (orderLineToDelete != null) order.OrderLines.Remove(orderLineToDelete); ctx.SaveChanges(); } </code></pre> <p>...would indeed <em>delete</em> the <code>orderLineToDelete</code> from the database.</p> <p>More details are <a href="http://msdn.microsoft.com/en-us/library/ee373856.aspx" rel="nofollow noreferrer">here</a> in section "<em>Considerations for Identifying and Non-identifying Relationships</em>".</p>
    singulars
    1. This table or related slice is empty.
    1. POIs it possible to remove child from collection and resolve issues on SaveChanges?
      singulars
      1. PTQuestion
    1. PTAnswer
    1. USCommunity
    1. USSlauma
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. POIs it possible to remove child from collection and resolve issues on SaveChanges?
      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. VTUpMod
    2. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTAcceptedByOriginator
    3. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    1. COAh so if if I make a composite key on the child entities EF will deal with this for me. Now that seems quite attractive.
      singulars
      1. PO
      1. USGraemeMiller
    2. COThat was great but I needed to add [Key, Column(Order = 0), DatabaseGenerated(DatabaseGeneratedOption.Identity)] public int OrderLineId { get; set; } to get it to not complain about identity insert.
      singulars
      1. PO
      1. USGraemeMiller
    3. CO@GraemeMiller: That's what I meant with "*You can make the OrderLineId an autogenerated identity if you want*" :) I forgot to mention that you need to do this in the *model* (with the DatabaseGeneratedOption) *and* in the *database*.
      singulars
      1. PO
      1. USSlauma
 

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