I'm trying to add a new ADO.Net Entity Data Model to an MVC project I am working on.
When I complete the wizard, choosing my db and tables (just a single table for now) I get an error ""Exception has been thrown by the target of an invocation." and it throws me back the add new item dialog.
At this point, an empty Data Model has been created in my project. If I then choose "Update Model From Database" and complete the wizard again, I get a similar error.
An exception of type 'System.Reflection.TargetInvocationException' occurred while attempting to update from the database. The exception message is: 'Exception has been thrown by the target of an invocation.'.
Any ideas? I have tried doing this in an empty project also and still no dice!
Alex
You could try creating the Entity Data Model manually using the EdmGen.exe tool. Hopefully that will give a bit more information about the error.
Try turning on the include exception faults behaviour
namespace DataService
{
[System.ServiceModel.ServiceBehavior(IncludeExceptionDetailInFaults = true)]
public class mydataservice : DataService<DataContext>
{
blah blah
I had similar issue. Look for similar names and missing mapping of forgen keys
I have had the same exeption, in my case it was my db(MySql) that had a table without a primary key, I just added a column "ID" and made it the primary key and voila! the exeption was gone :)
Related
I followed this post step by step but when I'm running it and enter to the view I created I get:
Model compatibility cannot be checked because the database does not contain model metadata. Ensure that IncludeMetadataConvention has been added to the DbModelBuilder conventions.
I dont know how to deal with it because I add Database.SetInitializer at the application_start and in the initializer I inherit DropCreateDatabaseIfModelChanges class, what am I missing?
Did you actually have the db created? Drop the db first to ensure its not there and let it create it and the proper model data should be initialized.
Could someone with some good knowledge answer this question please. Im having a problem with the schema in my Students.aspx page. I have done the walkthrough, but I get an error and I have copied the edmx file from the sample into my application and I still get the error. This is the error:
'EnrollmentDate' is not a member of
type 'SchoolModel.Person' in the
currently loaded schemas. Near simple
identifier, line 6, column 4.
I have also created a new EntityDataSource and I have the same problem. The sample works fine but I can't seem to get the EnrollmentDate and HireDate fields to be part of the 'SchoolModel.Person' Entity. The part which is Upto setting the EntityTypeFilter then I run the app and I get problems
It sounds like you're following the example on MSDN. By the end of the example, the fields EnrollmentDate and HireDate are no longer on the SchoolModel.Person class, they're on the subclasses SchoolModel.Instructor and SchoolModel.Student.
I faced the same problem while going through that walkthrough. The solution: Just delete the old EntityDataSource control on the page, put new EntityDataSource, configure it as given in walkthrough (with entity set name: People; EntityTypeFilter: Student or instructor), And every thing works as it should!!
Faraz
It sounds like you may have missed one or more EDS controls when you added the EntityTypeFilter attributes. Are you sure all your EDS controls that access students or instructors have EntityTypeFilter="Student" or EntityTypeFilter="Instructor"?
I have created a Entity named MediaItem which is Abstract and Game inherits form it. I create the database automatically and I get a table MediaItems and MediaItems_Game.
The issue is when I do the following in my ASP.Net Controller:
private Models.DBContainer dataModel = new DBContainer();
dataModel. ---> Intellisense shows me MediaItem but I can find no way to either navigate to or use MediaItems_Game, how can I solve this? i.e. How can I grab a list of 'Games' with some 'WHERE' constraints on another table (not pictured).
Any info is appreciated, thanks.
This is how inheritance in EF works. You have only single set of parent type. If you want to get just games you will use OfType method:
var games = dataModel.MediaItems.OfType<Game>().ToList();
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.
When trying to add a few items to the database I'm getting this error:
UpdateException was unhandled by user code
An error occurred while updating the entries. See the InnerException for details.
The InnerException contains this:
{"Column count doesn't match value count at row 1"}
I can't see anything wrong with the objects I'm trying to add, all the required values are filled.
Is there any way of viewing the query that causes the problem?
The method's code, if required:
[AcceptVerbs(HttpVerbs.Post)]
public ActionResult LaadVerrichtingenIn() {
int[] intArray = Array.ConvertAll<String, int>(Request.Form["selectedObjects"].Split(','), new Converter<String, int>(Convert.ToInt32));
List<Verrichting> gekozenVerrichtingen = new List<Verrichting>();
foreach(int i in intArray){
base._entities.AddToVerrichtingSet(((Dictionary<int, Verrichting>)Session["ingelezenVerrichtingen"])[i]);
gekozenVerrichtingen.Add(((Dictionary<int, Verrichting>)Session["ingelezenVerrichtingen"])[i]);
}
Session["ingelezenVerrichtingen"] = null;
base._entities.SaveChanges(); //Exception occurs here
return View("IngeladenVerrichtingen");
}
base._entities is an ADO.NET Entity Data Model.
Thanks
I'm not sure if there's a 'neater' way to do this with the Entity Framework, but if you're using SQL Server then I'd generally use the SQL Server Profiler to read the queries being executed against the server. If you're using a different database then there may be an equivalent - in any case it would probably be helpful if you let us know.
If you're using MySQL > 5.0.37 it has new query profiler functionality - this should be able to show you the queries being sent.
SQL server profiler will work fine if you're using SQL Server. Within the Entity Framework, you can use the ToTraceString method.
I've just come across the same problem while inserting data using the Entity Framework and MySQL. My hunch is, since I'm using double values, that the decimal separator "," is being misinterpreted as a field separator. I upgraded to Connector version 6.1.0, but still no luck. Maybe this is also going on in your case.
Check out this bug report.
BTW, I found that the following line of code works around the problem:
Thread.CurrentThread.CurrentCulture = new CultureInfo("en-US");