Let's say I have 2 models, Location and Item, that correspond to 2 tables in a database, represented in c# below. Is something like a PATCH request to /items/{itemId} appropriate to change the location id of an item to refer to a different location resource? This is the first time I've been in a situation where I want to change the parent of a resource so I am unsure of the appropriate method and route. I'm working with DTO (data transfer objects) so ideally what I want to do is acceptable so I can have just one DTO patch class for updates to the Item model.
public class Location {
public long Id { get; set; }
public ushort RoomNumber { get; set; }
public string Description { get; set; }
public List<Item> Items { get; set; }
}
public class Item {
public long Id { get; set; }
public string AssetNumber { get; set; }
public string SerialNumber { get; set; }
public long LocationId { get; set; }
public Location Location { get; set; }
}
Given that your url is /items/{itemId} and not something like /location/{locationId}/items/{itemId}, I don't think there's any thing special about changing the locationId versus any other property from a HTTP/Rest perspective.
And PATCH is a good way to make a partial change to a resource.
Related
I am receiving PostDTO object in the controller and I am mapping it to Post entity and updating database. The problem occurs because PostDTO doesn't have Status property and Post entity does have Status property, so when I map PostDTO to Post, Post.Status becomes null. I don't want it to be null, I want it to stay unaffected in database. I could retrieve post from database and manually map Status property but is there better solution for this?
public class PostDTO
{
public int Id { get; set; }
public string Title { get; set; }
public string Content { get; set; }
public bool Urgent { get; set; }
}
public class Post
{
public long Id { get; set; }
public string Title { get; set; }
public string Content { get; set; }
public bool Urgent { get; set; }
public string Status { get; set; }
}
var post = _mapper.Map<Post>(postDto); //here post.Status becomes null
You could either use an approach like this to ensure the field isn't updated:
https://stackoverflow.com/a/10271910/84206
OR you can first GET the entity from the database, so that the Status is populated from the database, then apply the DTO changes to the entity.
There's other approaches, but they can't really be applied with EF.
I'm creating an ASP.NET Core 3.1 Web API using OData v4.
I just made a GitHub repo here containing the entire solution, even the database project with dummy data.
Some blogs helped me along the way:
Experimenting with OData in ASP.NET Core 3.1
Supercharging ASP.NET Core API with OData
I've successfully created 3 basic endpoints that can be queried (Countries, Cities and Customers).
The Country and City endpoints work as expected, it is the Customer endpoint that causes some issues on $expand.
The Customer model looks like this (please note that I am currently using domain entities instead of DTO's because I want to get everything working smoothly first, before projecting them to DTO's):
public abstract class AppEntity : IAppEntity
{
[Key]
public int Id { get; set; }
}
public class Customer : AppEntity
{
public string Name { get; set; }
public string AddressLine1 { get; set; }
public string AddressLine2 { get; set; }
public virtual City City { get; set; }
public string VAT { get; set; }
public virtual List<CustomerEmailAddress> EmailAddresses { get; set; }
public virtual List<CustomerNote> Notes { get; set; }
}
With the following models acting as navigation properties:
public class CustomerEmailAddress : AppEntity
{
public Customer Customer { get; set; }
public string EmailAddress { get; set; }
public bool IsPrimary { get; set; }
}
public class CustomerNote : AppEntity
{
public Customer Customer { get; set; }
public DateTime DateTime { get; set; }
public string Message { get; set; }
}
Most of my queries are successful:
Just the collection: https://localhost:44309/api/customer
Expanding the City: https://localhost:44309/api/customer?$expand=City
On of the one-many relationships: https://localhost:44309/api/customer?$expand=Notes
But as soon as I try to expand 2 or more one-many properties or expand all (?$expand=*), I get an exception:
System.ArgumentOutOfRangeException: Index was out of range. Must be non-negative and less than the size of the collection. (Parameter 'index')
Any clue where this exception might be coming from?
My EdmModel is defined as:
IEdmModel GetEdmModel()
{
var odataBuilder = new ODataConventionModelBuilder();
odataBuilder.EntitySet<Country>("Country");
odataBuilder.EntitySet<City>("City");
odataBuilder.EntitySet<Customer>("Customer");
return odataBuilder.GetEdmModel();
}
Online shop I am working on has entity Order that has member DeliveryDetails.
The purpose of DeliveryDetails is to contain data which is specific to delivery method selected by user (e.g. Shipping or Pick Up From Store), while some details are common for all methods (e.g. Firstname, Lastname, PhoneNumber). I was thinking about structure similar to the following using inheritance:
public class Order {
// ....other props...
public DeliveryMethodType DeliveryMethodType { get; set; }
public DeliveryDetailsBase DeliveryDetails { get; set; }
}
public class DeliveryDetailsBase
{
public int Id { get; set; }
public string CustomerId { get; set; }
public Order Order { get; set; }
public int OrderId { get; set; }
public string Firstname { get; set; }
public string Lastname { get; set; }
public string PhoneNumber { get; set; }
}
public class DeliveryDetailsShipping : DeliveryDetailsBase
{
public string Street { get; set; }
public string Building { get; set; }
public string Appartment { get; set; }
public string PostalCode { get; set; }
public string City { get; set; }
public string Country { get; set; }
}
public class DeliveryDetailsPickupFromStore : DeliveryDetailsBase
{
public string StoreCode { get; set; }
}
However, I can't figure out how to make DeliveryDetails prop be assigned to different type of delivery method details depending on what method customer selected and how to fit it in EntityFramework on ASP.Core.
Workarounds I have already tried:
-> (1). Creating "super class" contatining props for ALL delivery methods and populate in db only those that are needed for selected delivery method (selection via setting enum DeliveryMethodType). OUTCOME: works, but with 1 big and ugly table featuring multiple nulls.
-> (2). In Order, creating prop DeliveryDetails which in turn embraces DeliveryDetailsPickupFromStoreDATA & DeliveryDetailsShippingDATA. OUTCOME: works, but with several related tables and quite a lot of ugly code checking selected type from enum, instantiating specific subclass for chosen delivery method and setting to null other unused subclasses.
TO SUM UP: Is there any more elegant and feasible way to organize this?
Is there any more elegant and feasible way to organize this?
Keep it simple, and inheritance isn't usually simple. :)
As a general rule I opt for composition over inheritance. It's easier to work with. Given an order that needs to be delivered to an address or to a store:
public class Order
{
public DeliveryMethod DeliveryMethod { get; set; } = DeliveryMethod.None;
public virtual OrderDeliveryAddress { get; set; } // should never be null.
public virtual OrderDeliveryStore { get; set; } // not null if delivery mode = store.
}
public class Address
{
public string Street { get; set; }
public string Building { get; set; }
public string Appartment { get; set; }
public string PostalCode { get; set; }
public string City { get; set; }
public string Country { get; set; }
}
public class OrderDeliveryAddress
{
public virtual Order Order { get; set; }
public virtual Address Address { get; set; }
}
public class Store
{
public int StoreId { get; set; }
public virtual Address { get; set; }
}
public class OrderDeliveryStore
{
public virtual Order Order { get; set; }
public virtual Store Store { get; set; }
}
Where DeliveryMethod is an Enum. { None = 0, ToAddress, ToStore }
When an order is placed the operator can choose to deliver it to an address, selecting the address of the customer, or entering a new address record; or they can deliver it to a store which can also set the OrderDeliveryAddress to the address of the store. You can establish checks in the database/system to ensure that the data integrity for the delivery method and referenced OrderDeliveryAddress/OrderDeliveryStore are in sync and raise any mismatches that might appear.
One consideration would be that when it comes to deliveries, you will probably want to clone a new Address record based on the customer address, or store address as applicable at the time of ordering rather than referencing their current address record by ID. The reason would be for historical integrity. An order will have been delivered to the address at that point in time, and if a customer address or store address changes in the future, past orders should still show the address that order was delivered.
EF Core has only implemented Table Per Hierarchy (TPH) inheritance.
Table Per Type (TPT) is still an open ticket (not implemented).
Table Per Concrete Type (TPC) is also still an open ticket (not implemented).
So, if TPH meets your requirements, you can follow this guide.
Basically, one table will be used and an extra column called Discriminator will be used to determine which implementation the record corresponds to.
If you are just getting started with Entity, my recommendation would be to not use inheritance and just use nullable columns for data that may or may not be needed depending on the type.
I am using VS2015 and have MVC5 web app. I want to use scaffolding feature to generate CRUD for my child entities: currently when generating the scaffolding it is NOT creating the views/edit/create for the IEnumerable collection 'Cities'.
I have googled but not found anything. Is there a Nuget package that does what I want. It should allow to add/delete/edit the cities maybe using partial view but should be auto-generated.
code:
public partial class Country
{
public int ID { get; set; }
public string Name { get; set; }
public string Color { get; set; }
public string Location { get; set; }
public virtual IEnumerable<Cities> Cities { get; set; }
}
public partial class Cities
{
public int ID { get; set; }
public string Name { get; set; }
public string TreLocation { get; set; }
public string Geo { get; set; }
}
Do you want an editable list of cities under each country?
Don't use mvc! In the time you spend figuring it out, you can probably learn angular. Which is far better for tis sort of thing.
However, back in the mists of time wise sages wrestled with this problem, for example....
Collection of complex child objects in Asp.Net MVC 3 application?
https://www.donnfelker.com/editable-grid-list-binding-in-mvc2/&ved=2ahUKEwiltefd9cngAhWjQxUIHe45AM4QFjACegQIARAB&usg=AOvVaw2z8iH5hZnObcnIMl3d4cyI
I have a User and an Organization class. They look like this
public class User
{
public int UserId { get; set; }
public string UserName { get; set; }
public string Email { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
public virtual ICollection<Organization> Organizations { get; set; }
}
public class Organization : EntityBase
{
public string Name { get; set; }
public string Description { get; set; }
public virtual ICollection<User> Users { get; set; }
}
And both inherit from an EntityBase class to get common fields like Id and created/updated tracking.
public abstract class EntityBase
{
public int Id { get; set; }
public DateTime Created { get; set; }
public virtual User CreatedBy { get; set; }
public DateTime Updated { get; set; }
public virtual User UpdatedBy { get; set; }
}
As denoted by the ICollection properties on both, there should be a many-to-many relation. However when my database is autogenerated I get incorrect foreign keys added to my tables
If I change the CreatedBy and UpdatedBy to be strings instead of User properties I get a join table, which is what I was looking for.
Is this a matter of Entity Framework simply being confused and I need to supply many-to-many configuration in the using fluent mappings, or have I done something wrong?
If you have multiple relationships you need to configure them manually by fluent API or using attributes,
Note:If you have multiple relationships between the same types (for
example, suppose you define the Person and Book classes, where the
Person class contains the ReviewedBooks and AuthoredBooks navigation
properties and the Book class contains the Author and Reviewer
navigation properties) you need to manually configure the
relationships by using Data Annotations or the fluent API
Here is the article from Microsoft.