I'm trying to query a WCF Data Service with oData. Everything works fine, but in a many to many relation the expand Function doesn't work. The Relation is: Product 1-* ProductOrder *-1 Order Here is my code to query the service:
var queryProductOrder = (DataServiceQuery<ProductOrder>)SessionHelper.context.ProductOrder.Expand(x=>x.Product);
var allProductOrders = await queryProductOrder.ExecuteAsync();
If I run this in debug mode and check the allProductOrder Object, there is no Product. The interesting fact is, that when I check the generated OData Query and run it over the browser, the Product gets expanded.
The query looks like this:
http://localhost:10000/ProductOrder()?$expand=Product
And the JSON-Result is expanded:
{"odata.metadata":"http://localhost:10000/$metadata#ProductOrder","value":[{"Product":{"id":1,"Name":"Die Sims","Tax_fk":1,"Price":"44.99","Description":"Lebenssimulation","Stock":"99.00","TotalOrder":"0.00","ProductUnit_fk":1,"Barcode":"121212121","MainImage_fk":null,"Tenant_fk":1,"PurchasePrice":null},"id":1,"Product_fk":1,"Order_fk":1,"Tenant_fk":1,"Amount":"10"}]}
Also confusing is the fact, that on other many to many relations the expand method works like it should.
Why it doesn't expand the allProductOrders Object? Why is the allProductOrders.First().Product object null but the generated OData query returns the Expanded data?
Related
I am using the following code to render a pager:
#Html.BootstrapPager(Request.QueryString("Page"), Function(index) Url.Action("Index", "Posts", New With {.page = index}), 14000, System.Web.Configuration.WebConfigurationManager.AppSettings("PageSize"), 15)
My problem is that If I use Model.Count in place of the 14000 then I only get 1 page of records since I am using skip and take in the repository to pull only the need records. How can i in the view access the total number of published records so that I don't have to hard code the value into the view right now?
The original pager code is here. I converted it to VBNET am using it. It works fine if the record count is hardcoded.
This is the repo:
Dim posts As IEnumerable(Of PostSummaryDTO)
Using db As BetterBlogContext = New BetterBlogContext
posts = db.be_Posts.OrderByDescending(Function(x) x.DateCreated).Select(Function(s) New PostSummaryDTO With {.Id = s.PostRowID, .PostDateCreated = s.DateCreated, .PostSummary = s.Description, .PostTitle = s.Title, .IsPublished = s.IsPublished}).Skip((Page - 1) * PageSize).Take(PageSize).ToList()
Return posts.ToList
End Using
You need two different methods in the lower layer - one to get the total count and one to get the desired page - and then call them both from your controller, passing both results in the model to the view. As such, the model cannot be a collection of records; it must be an object with a property for a collection of records and a property for the count. Either that or use the ViewBag to pass the count.
What we do in my office is have a service layer to contain the business logic and repository to handle the data access. There is a single method in the repository to return an IQueryable that provides access to all the records for a particular table. There are then one or more methods in the service that call that repository method and use it in different ways. In this case, there might be a GetTotalCount method and a GetPage method in the service. Both would call the same repository method to get the same IQueryable and then the first method would call Count on the result while the second method would call Skip and Take. As Skip and Take don't force execution of the query, you'd also call ToArray or the like in that second method. The service might also have a GetRecord method that you would pass an ID and call FirstOrDefault inside to get a single record with a matching ID. You can roll the service and repository into a single class if you want but I'd recommend separating the business logic from the data access.
A user can create groups
A group had to have created by a user
A user can belong to multiple groups
A group can have multiple users
I have something like the following:
Parse.Cloud.afterSave('Group', function(request) {
var creator = request.user;
var group = request.object;
var wasGroupCreated = group.existed;
if(wasGroupCreated) {
var hasCreatedRelation = creator.relation('hasCreated');
hasCreatedRelation.add(group);
var isAMemberOfRelation = creator.relation('isMemberOf');
isAMemberOfRelation.add(group);
creator.save();
}
});
Now when I GET user/me with include=isMemberOf,hasCreated, it returns me the user object but with the following:
hasCreated: {
__type: "Relation"
className: "Group"
},
isMemberOf: {
__type: "Relation"
className: "Group"
}
I'd like to have the group objects included in say, 'hasCreated' and 'isMemberOf' arrays. How do I pull that using the REST API?
More in general though, am I approaching this the right way? Thoughts? Help is much appreciated!
First off, existed is a function that returns true or false (in your case the wasGroupCreated variable is always going to be a reference to the function and will tis always evaluate to true). It probably isn't going to return what you expect anyway if you were using it correctly.
I think what you want is the isNew() function, though I would test if this works in the Parse.Cloud.afterSave() method as I haven't tried it there.
As for the second part of your question, you seem to want to use your Relations like Arrays. If you used an array instead (and the size was small enough), then you could just include the Group objects in the query (add include parameter set to isMemberOf for example in your REST query).
If you do want to stick to Relations, realise that you'll need to read up more in the documentation. In particular you'll need to query the Group object using a where expression that has a $relatedTo pointer for the user. To query in this manner, you will probably need a members property on the Group that is a relation to Users.
Something like this in your REST query might work (replace the objectId with the right User of course):
where={"$relatedTo":{"object":{"__type":"Pointer","className":"_User","objectId":"8TOXdXf3tz"},"key":"members"}}
I have a question...
I have a web service where the OperationContract are retrieve and update.
Using a cars example, I have the retrieve providing an object that contains a list of cars and how many cars. I have that configured through a class.
[OperationContract(Name = "**Retrieve**")]
[FaultContract(typeof(FaultInfo))]
[XmlSerializerFormat]
CarInfo Retrieve(CarRequest CarRetrieve);
[OperationContract(Name = "**Update**")]
[FaultContract(typeof(FaultInfo))]
[XmlSerializerFormat]
CarUpdateInfo Update(CarUPDRequest CarUpdate);
Now the retrieve I do not seem to have a problem with at all. It's looking like it's providing the information; the update, however, is not working.
The CarUPDRequest object is defined with different classes and one of those is a list of cars.
The class is constructed much the same as the CarUpdateInfo and that seems to work.
On the client, I know I can would call the update. But I construct the object CarUPDRequest on the client.
I have the service reference namespace like CarService. I can actually type CarService. (and get the list of class methods like the CarInfo and CarUPDRequest.
A couple of things I noticed is like the .Add for a collection defined by a list. On the client app, I DO NOT get the Add. However, if I try the same thing local on the CarService.cs, it will allow me to do the add:
Example:
CarUpd.Cars.car.add doesn't work on the client but does work on the server. Work as in is an option.
When using something like
var CarUpd = new CarUpdRequest();
Is there something I am missing here?
Any assistance on this would be greatly appreciated.
I solved my issue by doing a List CarUpd = new List();
Let's say I have database with two tables - Groups and Items.
Table Groups has only two columns: Id and Name.
Table Items has three columns: Id, GroupId and Name.
As you can see, there is one-to-many relation between Groups and Items.
I'm trying to build a web service using WCF and LINQ. I've added new LINQ to SQL classes file, and I've imported these two tables. Visual Studio has automatically generated proper classes for me.
After that, I've create simple client for the service, just to check if everything is working. After I call GetAllGroups() method, I get all groups from Groups table. But their property Items is always null.
So my question is - is there a way to force WCF to return whole class (whole Group class and all Items that belong to it)? Or is this the way it should behave?
EDIT: This is function inside WCF Service that returns all Groups:
public List<Group> GetAllGroups()
{
List<Group> groups = (from r in db.Groups select r).ToList();
return groups;
}
I've checked while debugging and every Group object inside GetAllGroups() function has it's items, but after client receives them - every Items property is set to null.
Most likely, you're experiencing the default "lazy-loading" behavior of Linq-to-SQL. When you debug and look at the .Items collection - that causes the items to be loaded. This doesn't happen however when your service code runs normally.
You can however enforce "eager-loading" of those items - try something like this:
(see Using DataLoadOptions to Control Deferred Loading or LINQ to SQL, Lazy Loading and Prefetching for more details)
public List<Group> GetAllGroups()
{
// this line should really be where you *instantiate* your "db" context!
db.DeferredLoadingEnabled = false;
DataLoadOptions dlo = new DataLoadOptions();
dlo.LoadWith<Group>(g => g.Items);
db.LoadOptions = dlo;
List<Group> groups = (from r in db.Groups select r).ToList();
return groups;
}
Do you get the Items collection populated now, when you call your service?
I want to load some data with a SP.
I've put a SP in a Linq to SQL Class and I don't know how to use it for loading it's data in a datagrid.
In LinqToSqlDomainService I can't figure out how to call a SP.
What steps should I use.
Any samples of this ? All samples use a table.
Thank's
This post should hopefully be of help:
http://blogs.msdn.com/brada/archive/2009/08/24/business-apps-example-for-silverlight-3-rtm-and-net-ria-services-july-update-part-24-stored-procedures.aspx
You can create empty view with the same structure of your sproc and map that stored procedure to your function in your DomainService
See sample on http://cid-289eaf995528b9fd.skydrive.live.com/self.aspx/Public/sproc.zip
I found the following excellent step-by-step guide at this site -
http://betaforums.silverlight.net/forums/p/218383/521023.aspx
1) Add a ADO Entity Data Model to your Web project; Select generate from database option; Select your Database instance to connect to.
2) Choose your DB object to import to the Model. You can expand Table node to select any table you want to import to the Model. Expand Stored Procedure node to select your Stored Precedure as well. Click Finish to finish the import.
3) Right click the DB model designer to select Add/Function Import. Give the function a name (same name as your SP would be fine) and select the Stored Procedure you want to map. If your SP returns only one field, you can map the return result to a collection of scalars. If your SP returns more than one field, you could either map the return result to a collection or Entity (if all the field are from a single table) or a collection of Complex types.
If you want to use Complex type, you can click Get Column button to get all the columns for your SP. Then click Create new Complex type button to create this Complex type.
4) Add a Domain Service class to the Web project. Select the DataModel you just created as the DataContext of this Service. Select all the entitis you want expose to the client. The service functions should be generated for those entities.
5) You may not see the Complex type in the Entity list. You have to manully add a query function for your SP in your Service:
Say your SP is called SP1, the Complex type you generated is called SP1_Result.
Add the following code in your Domain Service class:
public IQueryable<SP1_Result> SP1()
{
return this.ObjectContext.SP1().AsQueryable();
}
Now you can compile your project. You might get an error like this: "SP1_Result does not have a Key" (if you not on RIA service SP1 beta). If you do, you need to do the following in the service metadata file:
Added a SP1_Result metadata class and tagged the Key field:
[MetadataTypeAttribute(typeof(SP1_Result.SP1_ResultMetadata))]
public partial class SP1_Result
{
internal sealed class SP1_ResultMetadata
{
[Key]
public int MyId; // Change MyId to the ID field of your SP_Result
}
}
6) Compile your solution. Now you have SP1_Result exposed to the client. Check the generated file, you should see SP1_Result is generated as an Entity class. Now you can access DomainContext.SP1Query and DomainContext.SP1_Results in your Silverlight code. You can treat it as you do with any other Entity(the entity mapped to a table) class.
Calling a stored procedure is trivial. Import it as a function and then invoke the function as a member of the DDS. The return value is an ObservableCollection<> that you can use to set up the DataContext of the object you want to bind.
...unless you want to use it in a Silverlight RIA app via the magic code generated proxy, in which case your goose is cooked unless your result rows exactly match one of the entities. If you can meet that criterion, edit the DomainService class and surface a method that wraps the ObjectContext method.