I've a problem updating objects with the ADO.NET Data Services.
First I've create a service, which can load and store the data. Its a basic data context which implements the IUpdatable-interface.
After that, I've created a simple service-client. I just created it with the 'Add Service'-reference in Visual Studio. Basically this service seams to work. I can query for the objects and store new objects. However I cannot update objects.
This is my update-code on the client:
var ctx =
new TeamDataContext(new Uri("http://localhost:8637/TeamInfoService.svc"));
var team = ctx.Teams.First();
team.TeamName = "New Team Name";
ctx.UpdateObject(team);
ctx.SaveChanges();
What my main issue is, that IUpdatable.SetValue() isn't called for the object which I want to update. Only the IUpdatable.SaveChanges() is called without updating the objects on the server.
When I create a new object, the IUpdatable.SetValue is called on the server to set the property.
So what I am doing wrong? Are my expectations wrong? Is IUpdatable.SetValue supposed to be called when updating a object? Or do I need to do additional things to do updates?
Edit: I just watched the HTTP-requests between the client and the server. The client send a HTTP-Merge request with the changes. However I still don't know why the changes aren't stored.
I've just found out whats the issue and feel like an idiot right now. The TeamName-property was the Key of the object. Of course, when you change the key, it actually cannot find the object to update anymore. And therefore it cannot update the property.
So, never try to update the key of the object =)
Related
I am writing an application which communicates with an API and stores the response in a Meteor Collection so I can have the power of mongo to sort/filter.
I would like to clear the collection for every new result set. But a Meteor Collection is persistent.
What is the preferred way of clearing the collection? I know you can drop the meteor collection, but is that the preferred method?
Help appreciated. Thank you!
I would go about creating a local mongo collection which will be available on client side only. To create a client-side collection, just don't give it a name argument.
//This collection is client-only, and will not be sync with server
myCollection = new Mongo.Collection();
//To be more explicit, you can use `null` for the name:
myCollection = new Mongo.Collection(null);
Once you are done using the data empty the collection
myCollection.remove({});
myCollection.remove({}) is the syntax for removing all documents from a collection. This will only work on the server unless the collection is a client-side collection as per #Nakib's example. Otherwise documents can only be deleted by _id on the client side. Normally your allow/deny rules should block any attempt to delete anything on the client as it provides a great attack vector.
Not completely familiar with the Meteor best practice but if you were going to clear out an array in javascript the best practice would be to run the following.
myArrary.length = 0;
For more information I recommend this blog post by David Walsh where he details the reasoning behind zeroing out an array as follows:
Setting the length equal to zero empties the existing array, not
creating another array! This helps you to avoid pointer issues with
arrays as well.
This is an asp.net-mvc application and I am trying to add an object, specifically a list of user objects to the cache. I feel like I'm missing a key concept or component when it comes to caching data, so any help would be greatly appreciated.
var cache = new Cache();
cache["Users"] = users;
The second line throw's "Object reference not set to an instance of an object. The users variable is not null, I'm certain I'm not creating or using the cache correctly, but cannot find any information in MSDN or SO regarding the right way to set up a cache. What's my mistake?
try using Cache Like this it may works if you are using static methods
System.Web.HttpContext.Current.Cache
What to do when I want to make changes on my data Collection but I do not want to persist it? In other words, I want to make changes on minimongo, locally, but I do not want to spread it to world.
Use _collection.
MyCollection = new Meteor.Collection('my-collection');
// Subscribe as you see fit
Meteor.subscribe('my-publication');
// Now, to make updates locally you can access the documents in the collection without
// making any calls to the sever.
MyCollection._collection.insert({key:value});
MyCollection._collection.update({key:value}, {key:value});
Works with the usual mini-mongo operations.
This is undocumented and might change in future releases of Meteor without notice.
According to the docs, we can create a Collection and set its name as null. It will create an unmanaged (unsynchronized) local collection.
Unfortunately, it seems to not be possible to make local changes in synchronized collections.
You can create what I call a "local mirror" of a shared collection. Here's a gist with baisc functionality: https://gist.github.com/belisarius222/4715531
The idea is that you wire up a new local collection (new Meteor.Collection(null)) so that any change in the shared collection gets applied to the local collection too.
I am getting below error whilst trying to persist an object that has a collection of interfaces which I want to hold a couple of different types of objects. Seems to be happening almost randomly. Sometimes after restarting it works ok ( I might be doing something wrong though).
class CommentList {
#Persistent
#Join
ArrayList<IComment> = new ArrayList<IComment>();
}
somewhere else...
CommentList cl = new CommentList();
cl.addComment( new SimpleComment() );
cl.addComment( new SpecialComment() );
repo.persist( cl );
I can see the join table has been created in my DB along with ID fields for each of the Implementation classes of IComment.
SimpleComment and SpecialComment implement IComment. If I just add a SimpleComment it works fine. As soon as I start trying to add other types of objects I start to get the errors.
error im getting
java.lang.ClassCastException: Field "com.myapp.model.CommentList.comments" is a reference field (interface/Object) of type com.myapp.behaviours.IComment but DataNucleus is unable to assign an object of type "com.myapp.model.ShortComment" to this field. You can only assign this field to a type specified by the "implementation-classes" extension attribute.
at org.datanucleus.store.mapped.mapping.MultiMapping.setObject(MultiMapping.java:220)
at org.datanucleus.store.mapped.mapping.ReferenceMapping.setObject(ReferenceMapping.java:526)
at org.datanucleus.store.mapped.mapping.MultiMapping.setObject(MultiMapping.java:200)
at org.datanucleus.store.rdbms.scostore.BackingStoreHelper.populateElementInStatement(BackingStoreHelpe
r.java:135)
at org.datanucleus.store.rdbms.scostore.RDBMSJoinListStoreSpecialization.internalAdd(RDBMSJoinListStore
Specialization.java:443)
at org.datanucleus.store.mapped.scostore.JoinListStore.internalAdd(JoinListStore.java:233)
When it does save, if I restart the server and try to query for a list of the comments, I get null values returned.
I'm using mysql backend - if I switch to db4o it works fine.
Please let me know if any info would be useful.
If you have any idea where I might be going wrong or can provide some sample code for persisting collection of different objects implementing the same interface that would be appreciated.
Thanks for any help.
Tom
When I used interfaces I just enabled dynamicSchemaUpdates (some persistence property with a name like that) and FK's are added when needed. The log gives all SQL I think
I fixed this by specifying
<extension implemention-classes="SimpleComment SpecialComment"/>
for the field cl in my pacakge.jdo.
I am using Adobe Air to get data from SalesForce, and present it in a datagrid.
I am using a query to get the data, and then put it into an arraycollection that is bound to the datagrid, this works correctly and the data is displayed.
I have made the datagrid editable, and I am able to change the values in the datagrid, but I cannot find how to save the changes to the local database.
I am using the following code:-
protected function VisitReportGrid_changeHandler(event:ListEvent):void{
app.wrapper.save(VisitReportGridProvider)
}
But this has the following error when I try and compile it:-
1067: Implicit coercion of a value of type mx.collections:ArrayCollection to an unrelated type mx.data:IManaged.
Obviously I am doing this wrong, but I cannot find the correct syntax.
Thanks in advance for your help
Roy
This code is not enough to understand where actually is the problem
Need to know what is VisitReportGridProvider, what is wrapper.save() method.
**after comment:
F3DesktopWrapper.save():
public function save(item:IManaged):void
Saves the specified Managed object to the local database. You must make an explicit call to syncWithServer() to update the data on the salesforce server. However, do not call syncWithServer() too often (batch your save calls) as this may use up your alloted API usage. If the item is in conflict, the conflict will be resolved.
Parameters:
item:IManaged — The managed object to create or update.
you're passing parameter with type ArrayCollection which doesn't implement IManaged interface.
You need to pass the item in the ArrayCollection that was changed to the save function. Like:
acc.fieldCollection.updateObject(new AsyncResponder(function(o:Object, t:Object):void {
app.wrapper.save(o as Account);
}, function(e:Object):void {
}));