Im trying to save a rating against a place, I have the code below, but it doesnt seems to save rating (to the ratings table) for an existing entity
place.Ratings.Add(rating);
_placeRepository.AddPlaceIfItDoesntExist(place);
_placeRepository.Save();
This is the repository method
public void AddPlaceIfItDoesntExist(Place place)
{
var placeItem = context.Places.FirstOrDefault(x => x.GooglePlaceId == place.GooglePlaceId);
if(placeItem==null)
{
context.Places.Add(place);
}
else
{
context.Entry(placeItem).State = EntityState.Modified;
}
}
and this is the poco
public class Place
{
public Place()
{
Ratings = new List<Rating>();
}
public int Id { get; set; }
public string Name { get; set; }
public string GooglePlaceId { get; set; }
}
I think the crux of the problem is because i need to check if the place exists based on googleplaceid(a string) rather than the id (both are unique per place btw)
Here
context.Entry(placeItem).State = EntityState.Modified;
you just mark the existing placeItem object as modified. But it's a different instance than the passed place object, hence contains the orginal values.
Instead, replace that line with:
context.Entry(placeItem).CurrentValues.SetValues(place);
Alternatively, you can use the DbSetMigrationsExtensions.AddOrUpdate method overload that allows you to pass a custom identification expression:
using System.Data.Entity.Migrations;
public void AddPlaceIfItDoesntExist(Place place)
{
context.Places.AddOrUpdate(p => p.GooglePlaceId, place);
}
Related
I'm trying to fetch (in disconnected way) an entity with its all related entities and then trying to update the entity. But I'm getting the following error:
Attaching an entity of type 'Feature' failed because another entity of the same type already has the same primary key value.
public class Person
{
public int PersonId { get; set; }
public string Personname { get; set }
public ICollection Addresses { get; set; }
}
public class Address
{
public int AddressId { get; set; }
public int PersonId { get; set; }
public string Line1 { get; set; }
public string City { get; set; }
public string State { get; set; }
public Person Person { get; set; }
public ICollection<Feature> Features { get; set; }
}
// Many to Many: Represented in database as AddressFeature (e.g Air Conditioning, Central Heating; User could select multiple features of a single address)
public class Feature
{
public int FeatureId { get; set; }
public string Featurename { get; set; }
public ICollection<Address> Addresses { get; set; } // Many-To-Many with Addresses
}
public Person GetCandidate(int id)
{
using (MyDbContext dbContext = new MyDbContext())
{
var person = dbContext.People.AsNoTracking().Where(x => x.PersonId == id);
person = person.Include(prop => prop.Addresses.Select(x => x.Country)).Include(prop => prop.Addresses.Select(x => x.Features));
return person.FirstOrDefault();
}
}
public void UpdateCandidate(Person newPerson)
{
Person existingPerson = GetPerson(person.Id); // Loading the existing candidate from database with ASNOTRACKING
dbContext.People.Attach(existingPerson); // This line is giving error
.....
.....
.....
}
Error:
Additional information: Attaching an entity of type 'Feature' failed because another entity of the same type already has the same primary key value.
It seems like (I may be wrong) GetCandidate is assigning every Feature within Person.Addresses a new instance. So, how could I modify the GetCandidate to make sure that the same instance (for same values) is bing assisgned to Person.Addresses --> Features.
Kindly suggest.
It seems like (I may be wrong) GetCandidate is assigning every Feature within Person.Addresses a new instance. So, how could I modify the GetCandidate to make sure that the same instance (for same values) is bing assisgned to Person.Addresses --> Features.
Since you are using a short lived DbContext for retrieving the data, all you need is to remove AsNoTracking(), thus allowing EF to use the context cache and consolidate the Feature entities. EF tracking serves different purposes. One is to allow consolidating the entity instances with the same PK which you are interested in this case, and the second is to detect the modifications in case you modify the entities and call SaveChanges(), which apparently you are not interested when using the context simply to retrieve the data. When you disable the tracking for a query, EF cannot use the cache, thus generates separate object instances.
What you really not want is to let EF create proxies which hold reference to the context used to obtain them and will cause issues when trying to attach to another context. I don't see virtual navigation properties in your models, so most likely EF will not create proxies, but in order to be absolutely sure, I would turn ProxyCreationEnabled off:
public Person GetCandidate(int id)
{
using (MyDbContext dbContext = new MyDbContext())
{
dbContext.Configuration.ProxyCreationEnabled = false;
var person = dbContext.People.Where(x => x.PersonId == id);
person = person.Include(prop => prop.Addresses.Select(x => x.Country)).Include(prop => prop.Addresses.Select(x => x.Features));
return person.FirstOrDefault();
}
}
I had a class called Document, which I split into two entities, in order to separate an expensive binary field:
[Table("Document")]
public class Document
{
[Key]
public int Id { get; set; }
... other fields ...
[Required]
public virtual DocumentBinary DocumentBinary { get; set; }
}
[Table("Document")]
public class DocumentBinary
{
[Key, ForeignKey("Document")]
public int DocumentId { get; set; }
public Document Document { get; set; }
public byte[] DocumentData { get; set; }
}
So, everything works fine, both entities share the same database table and DocumentData is only loaded when it's needed.
However, when it comes to updating the Document entity, I get an error stating that 'DocumentBinary is required'.
When I remove the [Required] attribute from DocumentBinary virtual property, I get the following error:
The entity types 'Document' and 'DocumentBinary' cannot share table 'Documents' because they are not in the same type hierarchy or do not have a valid one to one foreign key relationship with matching primary keys between them.
I can obviously do something like:
var test = document.DocumentBinary;
before updating the document object:
documentRepository.Update(document);
This will then load the binary data on my request and save the changes without any issues, but the whole point is that I shouldn't need to do that.
This can be achieved using the fluent API. If you remove the data annotations and in your OnModelCreating add this, it should work.
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Entity<Document>().HasRequired(d => d.DocumentBinary).
WithRequiredDependent(db => db.Document);
}
I managed to resolve it by overriding my Update method in DocumentRepository:
public override void Update(Document document)
{
try
{
DataContext.Entry(document.DocumentBinary).State = EntityState.Modified; // added this line
DataContext.Entry(document).State = EntityState.Modified;
}
catch (System.Exception exception)
{
throw new EntityException("Failed to update document");
}
}
I know it probably does the same thing as me evaluating DocumentBinary by assigning it to 'test' variable, but it looks like a much cleaner solution.
I want to retrieve an object plus its filtered/ordered collection property using EF 5. However, my current code throws an exception:
The Include path expression must refer to a navigation property
defined on the type. Use dotted paths for reference navigation
properties and the Select operator for collection navigation
properties
Here is the class of the object I want to retrieve:
public class EntryCollection
{
[Key]
public int Id { get; set; }
public ICollection<Entry> Entries { get; set; }
...
}
And here is the definition of Entry:
public class Entry
{
[Key]
public int Id { get; set; }
public DateTime Added { get; set; }
...
}
I wanted to retrieve the EntryCollection which contains only the most recent entries, so here is the code I tried:
using (var db = new MyContext())
{
return db.EntryCollections
.Include(ec => ec.Entries.OrderByDescending(e => e.Added).Take(5))
.SingleOrDefault(ec => ec.Foo == "bar');
}
Any ideas?
You cant use OrderBy inside an include.
what about the following
using (var db = new MyContext())
{
return db.EntryCollections
.Where(ec => ec.Foo == "bar")
.Select(ec=> new Something{Entries = ec.Entries.OrderByDescending(e => e.Added).Take(5) }, /*some other properties*/)
.SingleOrDefault();
}
or do it in two seperate queries
i have a one to one relationship between two entity and whn i want set navigation property add duplication record tu my table
because my English is poor, i attach my Project for you Here
tnx
my code here:
here my Entity:
public partial class User
{
public int Id { get; set; }
public string Name { get; set; }
public string Lastname { get; set; }
public int UserType { get; set; }
}
public partial class Storage : User
{
public virtual Store Store { get; set; }
}
public partial class Store
{
public int Id { get; set; }
public string Name { get; set; }
public virtual Storage Storage { get; set; }
}
here my Add Store botton:
User u = (User)(comboBox1.SelectedItem);
Storage st = new Storage(u);
Store s = new Store(textBoxStorename.Text);
s.SetStorage(st);
s.Save(st);
and here my Store Class:
public partial class Store
{
public Store()
{
}
public Store(string name)
{
this.Name = name;
}
public void SetStorage(Storage s)
{
if (s != null)
{
this.Storage = s;
}
}
public void Save(Storage s)
{
using (var storekeeper = new TestContainer())
{
bool flag = false;
foreach (var item in storekeeper.Stores)
{
if (item.Equals(this))
{
flag = true;
}
}
if (flag)
{
MessageBox.Show("Duplicat Error", "", MessageBoxButtons.OK, MessageBoxIcon.Error);
return;
}
try
{
storekeeper.Users.Attach(s);
storekeeper.Stores.Add(this);
storekeeper.SaveChanges();
}
catch (Exception e )
{
MessageBox.Show(e.Message);
}
}
}
public override string ToString()
{
return this.Name;
}
}
The real problem here is your data model.
In any case, what's happening is you're recreating the User entity that already exists when you instantiate the new Storage instance. Storage inherits from User, so storage is an instance of user conceptually. The storage model, however, is different - Storage is a relationship table between User and Store.
By instantiating a new instance of Storage, copying the existing User object's properties to the base properties of the Storage instance, then simply attaching the Storage object to the Users DbSet, entity framework rightly thinks that the object is new and needs to be inserted - including the User entity object. The user record already exists, hence your duplicate key problem.
Solution: change your data model. No reason to have the 1..1 relationship entity "Storage". Simply create a nullable Store property in the User entity. If you want to enforce that an instance of Store can only be referenced by a single User, then the Store entity should either use the User.Id property as its primary key (with the FK relationship) or have a FK UserId property in Store that must be unique.
This should be a simple one involving EF Code first but I can't wrap my head around the documentation and all the examples I am finding are from older versions. I am working with the latest (4.1).
Anyway I have some models like:
public class Foo
{
public int ID { get; set; }
public Bar Bar { get; set; }
}
public class Bar
{
public int ID { get; set; }
public string Value { get; set; }
}
I used some scaffolding with Asp.Net MVC to create my controllers/repositories and when I create a 'Foo' object, it also creates a 'Bar' object even though I set the 'Bar' property from something stored in the database.
public class FooViewModel
{
public int ID { get; set; }
public int BarID { get; set; }
}
public ActionResult Create(FooViewModel foo)
{
var entity = new Foo()
{
ID = foo.ID,
Bar = _barRepository.Find(foo.BarID)
};
_fooRepository.InsertOrUpdate(entity);
_fooRepository.Save();
// more stuff
}
How can I use fluent syntax for EF in order to stop it from creating a new 'Bar' row in the database?
Update
Here is the generated repository code:
public void InsertOrUpdate(Foo foo)
{
if (foo.ID == default(int)) {
// New entity
context.Foo.Add(foo);
} else {
// Existing entity
context.Foo(foo).State = EntityState.Modified;
}
}
public void Save()
{
context.SaveChanges();
}
your _fooRepository and _barRepository need to share same DB context instance. If the are using two instances the Bar will be in added state.
The problem must be somewhere in your repository layer - using the same model directly with EF 4.1 produces the expected result - a new row in the Foos table with a bar FK column pointing to the existing Bar.