It seems like the official MongoDB C# driver is not supported in SilverLight. I want to use MongoDB on the server side and communicate the data via WCF to the silverlight client.
The problem is the Id property in my POCO - Since I can't import a non-silverlight project into the silverlight - I can't use [BsonId] or ObjectId in my POCO which should be used by both the server and the client.
I've seen questions here on SO about having the Id member as string, but represented as ObjectId in the DB, but I haven't seen solutions.
What's the best way to have
public string Id { get; set; }
in my class, but still enjoy the benefits of ObjectId on the server-side of things?
I've seen this page, I tried using SetIdMember and MapIdProperty, the _id was null on the inserted documents.
Checkout the documentation here for representation options: http://www.mongodb.org/display/DOCS/CSharp+Driver+Serialization+Tutorial#CSharpDriverSerializationTutorial-RepresentationSerializationOptions
Alternatively, you could use a Guid in both your code and in the database and not need to do mental translations when querying.
Related
I am running ASP.NET Core 2 application.
I have a local instance of SQL Server where I have a table with a column of type Geometry.
When I go to read this table I get the following errors:
Type Udt is not supported on this platform.
Error parsing column 4 (MyLocation)
However this issue only seems to occur in my API project which calls to a custom made Nuget package that handles the CRUD operations.
If I test the same code in the project that does the CRUD it reads and maps my object.
It is not a connection issue in the API for I can successfully read/write other tables that do not have a Geometry field in it.
What could I possible be missing?
Code:
MyController:
public async Task<IActionResult> Get(Guid Id)
{
var rec = await myRepo.Get<MyData>(id);
// then do stuff
}
*myRepo is injected into my controller.
public class MyData
{
public Guid Id {get;set;}
public IGeometry MyLocation {get;set;}
}
myRepo:
public async Task<TEntity> Get<TEntity>(object id)
where TEntity : class
{
_conn.Open();
return await _conn.GetAsync<TEntity>(id);
}
If this is .NET Core, then I suspect you could have significant issues using sqlgeography etc; UDTs essentially aren't yet implemented in .NET Core:
Additionally, the underlying types that you would want to load use native code; the geo/etc types are not, AFAIK, available in .NET Core.
If I'm wrong, I'm more than happy to try to make whatever changes we need to help make this work, but at the time of writing: I don't think this is going to work through any API (it is not specific to Dapper).
You might want to consider using ASP.NET Core on .NET Framework for today? reference .Net framework 4.5.2 from .Net Core 2.0 project
If this data does actually load from ADO.NET in .NET Core, then I'd be happy to fix whatever I've missed.
I am trying to write a JPA query to get the type for a particular entity, given the id of the entity. I have an abstract class Account, and concrete subclasses CustomerAccount and AdministratorAccount. The id is an attribute of the Account, so I am trying to construct a query to return the Type (i.e. foo.bar.CustomerAccount) given the ID of the account.
I tried the following:
String sql = "SELECT TYPE(a) from Account a where a.id = :userId";
But that doesn't seem to work. Any ideas? I'm using the google app engine jpa implementation (datanucleus) if that helps.
Firstly, FWIW you are using Google's JPA plugin which just happens to use some ancient jars provided by the DataNucleus project. You are not using DataNucleus JPA.
Secondly, the datastore "GAE/Datastore" and Google's JPA plugin are not likely to support JPQL "TYPE" since that came along after their plugin was developed.
Finally, you maybe would get the info you want in a more efficient way by just doing
Object obj = em.find(Account.class, id);
Class type = obj.getClass();
since this also inspects the L1/L2 caches
I am using Objectify as a data access layer in my GoogleAppEngine hosted application.
The problem comes when I try to persist a map. My bean looks like this:
#Entity
#Cached
class MyBean{
#Id
private Long id;
#Embedded
Map<String, String> parameters = new HashMap<String, String>();
public MyBean(){}
//getters and setters below
}
First of all note that the map 'parameters' is not private, it was throwing a JRE exception.
When saving the map everything goes well. When retreiving it from the DataStore it fails.
My workaround is to use the #Serialized annotation. This is just a workaround since what I want to acheive is to use the expando feature of GAE Datastore.
According to the objectify doc I'm doing the right operations.
Exception details:
Caused by: java.lang.NullPointerException at
com.googlecode.objectify.impl.Transmog.loadSingleValue(Transmog.java:364)
at
com.googlecode.objectify.impl.load.EmbeddedMapSetter.safeSet(EmbeddedMapSetter.java:65)
at
com.googlecode.objectify.impl.load.CollisionDetectingSetter.set(CollisionDetectingSetter.java:37)
at
com.googlecode.objectify.impl.Transmog.loadSingleValue(Transmog.java:359)
at com.googlecode.objectify.impl.Transmog.load(Transmog.java:340) at
com.googlecode.objectify.impl.ConcreteEntityMetadata.toObject(ConcreteEntityMetadata.java:203)
at
com.googlecode.objectify.impl.QueryImpl$ToObjectIterator.translate(QueryImpl.java:668)
at
com.googlecode.objectify.impl.QueryImpl$ToObjectIterator.translate(QueryImpl.java:657)
at
com.googlecode.objectify.util.TranslatingIterator.next(TranslatingIterator.java:35)
Embedded maps were poorly supported in Objectify3, and should not have been publicly announced. The section on #Embedded Map has been removed from the Objectify3 documentation.
Objectify4 supports maps extensively, including these expando-style maps:
Map (or any primitive)
Map (key references)
Map (embedded classes
In addition, there is a #Mapify annotation that lets you take a normal collection of objects, pick one property out as a key, and store that as a Map.
Unfortunately Objectify4's documentation is not ready at this time. However, the source code is in active use by several parties. If you feel daring, build from trunk.
I also recommend using Objectify 4 - I've upgraded my app and found it fairly easy to do. I much prefer the support for fields of the type Map in particular.
To answer the question, you should never put #Embedded onto an array containing only primitives. So you don't need to specify #Embedded on your map because String is primitive in the Google App Engine Datastore.
I have combination of RIA services and nHibernate. nHibernate is configured to use identity on database side. So new Entities are sent with 0 for id. nHibernate works as it should. It updates generated keys form database and updates entites.
I have example with compositional hierarchy. My entity is complex it has two collections.
InvestObject
- MaterialItems
- WorkItems
I work with this structure in one unit of work. Geting and showing data in Silverlight app is no problem. But if I try to add more than one item in MaterialItems collection on client side, when saving I get this error:
Submit operation failed. Invalid
ChangeSet : Only one entry for a given
entity instance can exist in the
ChangeSet. at
System.ServiceModel.DomainServices.Server.ChangeSet.ValidateChangeSetEntries(IEnumerable1
changeSetEntries) at
System.ServiceModel.DomainServices.Server.ChangeSet..ctor(IEnumerable1
changeSetEntries)
There is a quick fix on client side, just to generate some dummy negative ids, for Material. This works for RIA and save is propagated to server side. But then nHibernate fires error, beacuse it expects 0 for all new Ids not a given value ( ). So this is not OK.
Finally I tricked nHibernate by reseting back all new Ids to 0. But this does not make me happy. It is messy ugly solution.
Please help
It's been a while since I've done this so the details are hazy but I think you basically can't use IDs that are generated in the DB with RIA services. We used the HiLo algorithm instead.
I'm stuck on my server part.
I thing it would be fine if I make an REST architecture but I'm not sure.
My application is that an identitied user edit his name, age, hobbies...and I want to stock all the informations of all the users on my data server. Then, I could send the information of a user to another in a ListView with an adaptater.
Any idea to help me?
Thanks in advance
I have recently added a series of posts to my blog that may help. It covers creating a RESTful service using Java EE technologies on the GlassFish server. The example produces consumes XML, but could easily be adapted to handle JSON.
Part 1 - The Database Model
Part 2 - Mapping the Database Model to JPA Entities
Part 3 - Mapping JPA Entities to XML using JAXB
Part 4 - The RESTful Service