Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>See the following code I use to easily attach a disconnected object back to the graph, assuming we're now going to save it.</p> <pre><code> public static class EntityFrameworkExtensions { /// &lt;summary&gt; /// This class allows you to attach an entity. /// For instance, a controller method Edit(Customer customer) /// using ctx.AttachAsModified(customer); /// ctx.SaveChanges(); /// allows you to easily reattach this item for udpating. /// Credit goes to: http://geekswithblogs.net/michelotti/archive/2009/11/27/attaching-modified-entities-in-ef-4.aspx /// &lt;/summary&gt; public static void AttachAsModified&lt;T&gt;(this ObjectSet&lt;T&gt; objectSet, T entity) where T : class { objectSet.Attach(entity); objectSet.Context.ObjectStateManager.ChangeObjectState(entity, EntityState.Modified); } /// &lt;summary&gt; /// This marks an item for deletion, but does not currently mark child objects (relationships). /// For those cases you must query the object, include the relationships, and then delete. /// &lt;/summary&gt; /// &lt;typeparam name=&quot;T&quot;&gt;&lt;/typeparam&gt; /// &lt;param name=&quot;objectSet&quot;&gt;&lt;/param&gt; /// &lt;param name=&quot;entity&quot;&gt;&lt;/param&gt; public static void AttachAsDeleted&lt;T&gt;(this ObjectSet&lt;T&gt; objectSet, T entity) where T : class { objectSet.Attach(entity); objectSet.Context.ObjectStateManager.ChangeObjectState(entity, EntityState.Deleted); } public static void AttachAllAsModified&lt;T&gt;(this ObjectSet&lt;T&gt; objectSet, IEnumerable&lt;T&gt; entities) where T : class { foreach (var item in entities) { objectSet.Attach(item); objectSet.Context.ObjectStateManager.ChangeObjectState(item, EntityState.Modified); } } } </code></pre>
    singulars
    1. This table or related slice is empty.
    1. POEntityFramework: Update single field with detached entity
      singulars
      1. PTQuestion
    1. PTAnswer
    1. This table or related slice is empty.
    1. USAdam Tuliper - MSFT
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    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. VTUpMod
    1. COYes, this attaches easily but it is also expensive because by setting the entity state to `Modified` EF will send a full update command to the DB with *all* scalar properties, no matter if they really changed or not. This is kind of "brute force" updating.
      singulars
      1. PO
      1. USSlauma
    2. COyes but unfortunately in most situations we don't know what's changed on the web. We go from a page to some disconnected item. This is even more the case with MVC, where your model is passed in as a disconnected item. You then need to either send that to the db or load an object and then merge the model with this object. In that case you've not only saved every property, but had to do a full load as well. If you AttachAsModified, you can save without a load first. Unless your data page is approaching an 8k limit (or larger with varchar(max) items, Im not sure the perf is going to be an issue.
      singulars
      1. PO
      1. USAdam Tuliper - MSFT
    3. COI agree. If you don't know what has changed it's a working approach. I had the feeling from the question though that @cadmium is in a situation where he knows which properties did change. But I might be wrong.
      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