I have two simple models in .net backend based Azure Mobile Service Project, as shown below & I am not able to query the child table (querying parent table, UserItem, works just fine)
(The Id is nvarchar(128) & is autogenerated as newId by DB)
public class AnswerItem: EntityData
{
public string Content { get; set; }
public UserItem By { get; set; }
public QuestionItem ForQuestion { get; set; }
public double Rating { get; set; }
public string Comment { get; set; }
}
& a child to this UserItem Table as shown below
public class QuestionItem: EntityData
{
public string Content { get; set; }
public bool IsAnswered { get; set; }
public int NumberOfAnswers {get; set;}
public UserItem By { get; set; }
public string ById { get; set; }
public string AtLocation { get; set; }
}
As you notice, the QuestionItem has a FK relationship to UserItem table on ById field (Referencing Id field in UserItem Table)
The issue is I am getting a Bad Request error when I try to query the data from child table
Following are some queries that I tried
private IMobileServiceTable<QuestionItem> questionTable = App.MobileService.GetTable<QuestionItem>();
questions = await questionTable.Where(x=>x.IsAnswered==true).ToCollectionAsync(); (Does not Work)
questions = await questionTable.Where(x=>x.ById="UserIdGoesHere").ToCollectionAsync(); (Does Not Work)
questions = await questionTable.Where(x=>x.Content.StartsWith("q")).ToCollectionAsync(); (This Works)
questions = await questionTable.ToCollectionAsync(); (This Works as well)
If I fire a TSQL query in Sql Server Object explorer they all return correct values.
I am at my wits end on what could be wrong with my approach.
Any help is really appreciated.
Thanks
Supreet
Investigating further the Request it was generating was like this
192.168.2.4:50002/tables/QuestionItem?$filter=(byid eq 'myUniqueGuId')
analyzing fiddler output shows this error
"The query specified in the URI is not valid. Could not find a property named 'byid' on type 'x2Service.DataObjects.QuestionItem'"
Off course there is no fields in the table by the name of 'byid' the one I have is called 'ById' Its the JsonProperty adorner that changed it [JsonProperty(PropertyName = "byid")] In my client class.
Removed the Json Property & it worked just fine
Related
I've a situation where entity framework core (2.0) is performing additional work to a parent table when I update a row in a child table. I've pin-pointed the cause to a value not being set in the unflattened object tree produced by AutoMapper (I'm not saying it is an error in AutoMapper; it's probably more to do with my code).
I'm using ASP.NET Core 2.0, C#, EF Core 2.0 and AutoMapper for the API development side. The database already exists and the EF classes scaffolded from it.
To keep it short, the child table is Note and the parent table is NoteType. The EF classes (extraneous columns removed) are as follows :
//Entity classes
public partial class Note
{
public int NoteBookId { get; set; }
public short NoteSeqNo { get; set; }
public short NoteTypeId { get; set; }
public string NoteText { get; set; }
public NoteBook NoteBook { get; set; }
public NoteType NoteType { get; set; }
}
public partial class NoteType
{
public NoteType() { Note = new HashSet<Note>(); }
public short NoteTypeId { get; set; }
public string NoteTypeDesc { get; set; }
public ICollection<Note> Note { get; set; }
}
//DTO class
public class NoteDto
{
public int NoteBookId { get; set; }
public short NoteSeqNo { get; set; }
public short NoteTypeId { get; set; }
public string NoteTypeNoteTypeDesc { get; set; }
public string NoteText { get; set; }
}
public class NoteTypeDto
{
public short NoteTypeId { get; set; }
public string NoteTypeDesc { get; set; }
}
(NoteBookId + NoteSeqNo) is Note's primary key.
NoteTypeId is the NoteType's primary key.
Configuration
This is the AutoMapper configuration:
// config in startup.cs
config.CreateMap<Note,NoteDto>().ReverseMap();
config.CreateMap<NoteType,NoteTypeDto>().ReverseMap();
Read the data
As a result of data retrieval I get the expected result and the parent note type description is populated.
// EF get note in repository
return await _dbcontext.Note
.Where(n => n.NoteId == noteId && n.NoteSeqNo == noteSeqNo)
.Include(n => n.NoteType)
.FirstOrDefaultAsync();
// Get note function in API controller
Note note = await _repository.GetNoteAsync(id, seq);
NoteDto noteDto = Mapper.Map<NoteDto>(note);
Example JSON result:
{
"noteBookId": 29,
"noteSeqNo": 19,
"noteTypeId": 18,
"noteTypenoteTypeDesc": "ABCDE",
"noteText": "My notes here."
}
Update the data
When the process is reversed during an update, the API controller maps the dto to the entity
Mapper.Map<Note>(noteDto)
Then when it is passed to EF by the repository code, EF tries to add a NoteType row with id 0. The unflattened object tree looks like this:
Note
NoteBookId = 29
NoteSeqNo = 19
NoteTypeId = 18
NoteTypeNoteTypeDesc = "ABCDE"
NoteText = "My notes updated."
NoteType.NoteTypeDesc = "ABCDE"
NoteType.NoteTypeId = 0
The parent id column (NoteType.NoteTypeId) value is 0 and is not assigned the value of 18 which is what I expected.
(During debugging I manually set NoteType.NoteTypeId to 18 to ensure EF did nothing with it).
To work around this at the moment I nullify the NoteType in the Note in the repository code.
Should I expected AutoMapper to populate all the parent properties with setters or have I missed some configuration? Perhaps there is a glaring flaw in my approach?
When AutoMapper reverses the mapping, it has to collect all information for nested objects from the flat object. Your DTO only carries a value for the mapping NoteType -> NoteTypeDesc. Not for NoteType -> NoteTypeId, so AM really doesn't have any idea where to get that value from.
If you want to rely on flattening only, the only way to change that is to add a flattened NoteTypeId to the DTO besides the unflattened one:
public class NoteDto
{
public int NoteBookId { get; set; }
public short NoteSeqNo { get; set; }
public short NoteTypeId { get; set; } // Not flattened
public short NoteTypeNoteTypeId { get; set; } // Flattened
public string NoteTypeNoteTypeDesc { get; set; }
public string NoteText { get; set; }
}
The alternative is to add this to your mapping:
config.CreateMap<Note, NoteDto>()
.ForMember(dest => dest.NoteTypeId,
e => e.MapFrom(src => src.NoteType.NoteTypeId))
.ReverseMap();
MapFrom-s (including the default unflattening) are reversed now. You can drop ReverseMap and create the maps, ignore Note.NoteType or ignore the offending path, Note.NoteType.NoteTypeDesc.
I have a constructed a model using code first in C#. The model literally represents a container element for a website building application, in other words, the model defines a Div tag or some such HTML element. Like a Div tag which can contain multiple child elements, I have tried to represent this in my model, but the scaffolding to the DB, does not give me what I'd expect.
I should get a new many to many joins table, but instead I only get a single column in the DB which expects a single int data type.
Here is the model:
public class ElementContainer
{
public int ElementContainerID { get; set; }
public int PageId { get; set; }
public int? ParentElementContainerID { get; set; }
public string ElementContainerName { get; set; }
public ElementType ElementType { get; set; }
public string ElementClass { get; set; }
public PageAsset PageAsset { get; set; } // content of container
public List<ElementContainer> NestedContainers { get; set; }
}
The last line is the self-referential attribute which just appears as a column called ElementContainer_ElementContainerID
Thanks in advance!
I agree with Bahman, DB first is easier.
While I haven't tried to do what you are trying, your code looks like a self-Join that would do exactly what you describe.
This is a One-to-Many relationship. EF Navigation will pull a List of all nested children containers.
If you want to create a many-to-many relationship with EF Code-First, you should create another Entity
public class ContainerChildren
{
public int ElementContainerID { get; set; }
public List<ElementContainer> NestedContainers { get; set; }
}
this reference should help you to get the exact idea http://blogs.msdn.com/b/wriju/archive/2011/05/14/code-first-ef-4-1-building-many-to-many-relationship.aspx
I keep getting error when I try to access a model from an edit or details action.
The model backing the 'InjuriesContext' context has changed since the
database was created. Consider using Code First Migrations to update
the database (http://go.microsoft.com/fwlink/?LinkId=238269).
First I tried adding a migration even though I was sure I hadn't changed anything. Still recieved the same error after an update-database.
Then I removed all the migrations and the database and started a clean database with an inital migration and update. Same error. Nothing was changed.
Model is:
public class InjuriesContext : DbContext
{
public InjuriesContext()
: base("DBCon")
{
}
public DbSet<Patient> Patients { get; set; }
public DbSet<Injury> Injuries { get; set; }
}
public class Injury
{
public int Id { get; set; }
public string Type { get; set; }
public int PatientId { get; set; }
}
Here is controller --
public ActionResult Edit(int id = 0)
{
Injury injury = db.Injuries.Find(id);
if (injury == null)
{
return HttpNotFound();
}
return View(injury);
}
It errors on the injuries.find. I do not have any injuries entered so I expect it to return a 404 like my other controllers but it doesn't like something about this. The only difference between this and my other models is the y to ies for plural. Does Entity Framework not handle this?
There should not be any plural restriction, as you defined everything clearly in your classes anyway.
Have you created the Injuries table?
I belive the table Injury will get created automatically. the variable injury might be a bit close, but I have to test this myself.
Rather try:
public class Injury
{
[Key]
public int Id { get; set; }
[Required]
public string Type { get; set; }
[Required]
public int PatientId { get; set; }
}
private InjuriesContext db = new InjuriesContext();
Injury objInjury = db.Injuries.Find(id);
if (objInjury == null)
{
return HttpNotFound();
}
return View(objInjury);
Hope this helps
It turns out my issue was with multiple contexts. I thought you had to create a separate context for each model class. Apparently Entity Framework needs one context. I went through and created a class for my context and put all my DBsets in that class.
public class ProjContexts : DbContext
{
public ProjContexts()
: base("ProjDBCon")
{
}
public DbSet<Patient> Patients { get; set; }
public DbSet<PreHosp> PreHosps { get; set; }
public DbSet<UserProfile> UserProfiles { get; set; }
public DbSet<Injury> Injuries { get; set; }
}
}
Then I removed all the migrations as per this post and enabled the migrations again did an add migration and update then I got the expected result.
Bottom Line--- Don't have multiple context classes in your project. Not sure if this is possible but after changing the above everything is working as expected. Not sure why it was working when I had two separate contexts and added the third? Maybe because they had foreign keys with one another?
I am using MVC3 and Entity Framework. I have a class called User with 20 different properties. I have already created a database and filled it with some data. I want to break out the Addresses property and make it it's own class.
namespace NameSpace.Domain.Entities
{
public class User
{
public int UserId { get; set; }
...
...
public string AddressOne { get; set; }
public string AddressTwo { get; set; }
}
}
I want to break out both Addresses like so
namespace NameSpace.Domain.Entities
{
public class User
{
public int UserId { get; set; }
...
...
public Addresses Addresses { get; set; }
}
public class Addresses
{
public string AddressOne { get; set; }
public string AddressTwo { get; set; }
}
}
HERE'S MY QUESTION:
Since I already have the data table filled with data, how can I update this in the Server Explorer?
Thanks ( if you need more info please let me know )
If you are using EF code first 4.3 you can use the concept of migrations to achive what you want.
You will need to do a code based manual migration since you change is a bit to advanced for the framework to figure it out itselfe.
Further reading: http://blogs.msdn.com/b/adonet/archive/2012/02/09/ef-4-3-code-based-migrations-walkthrough.aspx
I have a datamodel like
ModelA which contains a Collection.
ModelB contains a Collection as a backreference. That is failing because of cyclic references if I query with Include("ModelB"). Not good but I solved that via setting ModelB.List=null for each element.
The problem now is submitting a changed ModelA tree: I am adding ModelB-entities to ModelA.ModelB[]. Now the UpdateEntity function is complaining the it could not add elements of type ModelB which are declared static. The JSON deserializer is creating static arrays.
How is it possible with the combination of upshot/MVC4 to submit datamodels which are not completely flat? As it is not possible right now to create your own DTO objects where you might figure out something I am stuck now...
After investigating the error a bit better, I think the problem is the cyclic backreference:
The ModelA->ModelB->ModelA is breaking the storage of the data. "Could not add data of type ModelA to type ModelB".
As I mentioned the backreference was set to Null because the cyclic ref serialisation problem...
I hope the will be some easier way on doing more manually with DTO objects where I have mroe control.
Please see also: MVC 4, Upshot entities cyclic references for the beginning of the journey...
To solve the cyclic backreference, you can use the ignoreDataMember attribute:
public class Customer
{
[Key]
public int CustomerId { get; set; }
public string Name { get; set; }
public string Address { get; set; }
public double Latitude { get; set; }
public double Longitude { get; set; }
public virtual ICollection<Delivery> Deliveries { get; set; }
}
public class Delivery
{
[Key]
public int DeliveryId { get; set; }
public string Description { get; set; }
public bool IsDelivered { get; set; }
[IgnoreDataMember]
public virtual Customer Customer { get; set; }
public virtual int CustomerId { get; set; }
}
I posted a working solution to your problem in a different question: https://stackoverflow.com/a/10010695/1226140