public class AcsBatchingDbContext : DbContext
{
public DbSet<CardHolder> CardHolders { get; set; }
public DbSet<AccessCard> AccessCards { get; set; }
}
public class CardHolder
{
public int CardHolderId { get; set; }
public ICollection<AccessCard> AccessCards { get; set; };
}
public class AccessCard
{
public int AccessCardId { get; set; }
public CardHolder CardHolder { get; set; }
}
When I try to get AccessCards
using (var db = new AcsBatchingDbContext())
{
var cards = db.AccessCards.ToList();
}
Where card.CardHolder = null
Why? Why EF doesnt grab the CardHolder?
Another question:
Why this expression doesnt compile?
db.AccessCards.Include(x => x.CardHolder).ToList();
Why the only options is to use is
db.AccessCards.Include("CardHolder").ToList();
You should use include to load CardHolder entity.
(This requires using System.Data.Entity;)
db.AccessCards.Include(x => x.CardHolder).ToList();
Alternatively, you can apply Include like this;
db.AccessCards.Include("CardHolder").ToList();
Related
I have SQLite db and these EF models and context.
Models and Context
public class CardHolder
{
public int CardHolderId { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
public string PhoneNumber { get; set; }
public string EmailAddress { get; set; }
public string TenantName { get; set; }
public ICollection<AccessCard> AccessCards { get; set; }
}
public class AccessCard
{
public int AccessCardId { get; protected set; }
public CardHolder CardHolder { get; set; }
public DateTime ActivationDate { get; protected set; }
public bool ActivationProcessed { get; set; }
public DateTime? DeactivationDate { get; protected set; }
public string DeactivationReason { get; set; }
public bool DeactivationProcessed { get; set; }
}
public class MyContext : DbContext
{
public DbSet<CardHolder> CardHolders { get; set; }
public DbSet<AccessCard> AccessCards { get; set; }
}
And the Main program
class Program
{
static void Main(string[] args)
{
using (var db = new MyContext())
{
var cardHolders = db.CardHolders.Include("AccessCard").ToList();
}
}
}
Question1: Why do I get this exception
System.InvalidOperationException: 'A specified Include path is not
valid. The EntityType 'SQLiteDemo.Models.CardHolder' does not declare
a navigation property with the name 'AccessCard'.'
If I replace it with
var cardHolders = db.CardHolders.Include("AccessCards").ToList();
I get another error:
SQL logic error no such column: Extent2.CardHolder_CardHolderId
What is wrong with Entity Framework?
Question2: Why cant I use arrow function in Include statement, it doesnt compile at all?
var cardHolders = db.CardHolders.Include(x => x.AccessCards).ToList();
Question3: Why do I need to use Include at all if my ICollection association property AccessCards is NOT virtual - that means eager loading must work by itself!
Why the hell it is so problematic and buggy? Nothing works as it should :(
1 - You have a typo as you have already determined :)
1B - "SQL logic error no such column: Extent2.CardHolder_CardHolderId"
EF isn't finding your FK. You could add it to your AccessCard model:
public int CardHolderId { get; set; }
2 - You need to pull in the LINQ extensions. Make sure you have both of these using statements at the top:
using System.Data.Entity;
using System.Linq;
3 - You, like many others, are misunderstanding lazy loading. Eager loading still requires an Include() to fetch related data. Lazy loading only fetches the relations when you access them.
I have two related Entity Framework 6 classes in my data layer.
public class Order
{
public int Id { get; set; }
public virtual SalesStatus SalesStatus { get; set; }
}
public class SalesStatus
{
public SalesStatus()
{
Orders = new List<Order>();
}
public int Id { get; set; }
public string Name { get; set; }
public virtual List<Order> Orders { get; set; }
}
public class OrderVM
{
public int Id { get; set; }
public SalesStatus SalesStatus { get; set; }
}
I am using Automapper to map these to my view models and back again.
cfg.CreateMap<Order, OrderVM>()
.MaxDepth(4)
.ReverseMap();
The status entity is used to populate a drop down list.
In my method I am taking the selected value and trying to update the order record to the new selected status.
private bool SaveOrderToDb(OrderVM orderVM)
{
using (var db = new MyContext())
{
var order = AutomapperConfig.MapperConfiguration.CreateMapper().Map<OrderVM, Order>(orderVM);
order.SalesStatus = db.SalesStatuses.Find(Convert.ToInt16(orderVM.SalesStatusSelectedValue));
db.Set<Order>().AddOrUpdate(order);
db.SaveChanges();
}
return true;
}
This does not update the relationship in the database. Why? What am I missing?
It could be very basic question but i have stuck with this
I have an Entity Structure like this one below
public class OrderTagGroup : Entity
{
public virtual string Name { get; set; }
public virtual List<OrderTag> OrderTags { get; set; }
}
public class OrderTag : Entity
{
public virtual string Name { get; set; }
public virtual int? OrderTagGroupId { get; set; }
}
and Its respective DTO is
public class OrderTagGroupDto : EntityDto
{
[Required]
public string Name { get; set; }
public List<OrderTagDto> OrderTags { get; set; }
}
public class OrderTagDto : EntityDto
{
[Required]
public string Name { get; set; }
public int? OrderTagGroupId { get; set; }
}
I have added the Auto mapping as well like this
Mapper.CreateMap<OrderTagGroup, OrderTagGroupDto>();
Mapper.CreateMap<OrderTagGroupDto, OrderTagGroup>();
Mapper.CreateMap<OrderTag, OrderTagDto>();
Mapper.CreateMap<OrderTagDto, OrderTag>();
Here is my Repository update
public void UpdateOrderTagGroup(OrderTagGroupDto OrderTagGroup)
{
var group = _OrderTagGroupRepo.Get(OrderTagGroup.Id);
if (group != null && group.Id > 0)
{
Mapper.Map<OrderTagGroupDto, OrderTagGroup>(OrderTagGroup,group);
}
}
My Question is, whenever my OrderTagGroupDTO goes for the update, it creates a new row in the DB and previous entry is not deleted.
Could you please help me where i am wrong ?
Automapper is for entity->DTO ..
NEVER use automapper or similar for DTO->entity it's NOT designed for that
For DTO->entity you should 'always' do it 'manually'
I want to remove a row in database and insert it again with the same Id, It sounds ridiculous, but here is the scenario:
The domain classes are as follows:
public class SomeClass
{
public int SomeClassId { get; set; }
public string Name { get; set; }
public virtual Behavior Behavior { get; set; }
}
public abstract class Behavior
{
public int BehaviorId { get; set; }
}
public class BehaviorA : Behavior
{
public string BehaviorASpecific { get; set; }
}
public class BehaviorB : Behavior
{
public string BehaviorBSpecific { get; set; }
}
The entity context is
public class TestContext : DbContext
{
public DbSet<SomeClass> SomeClasses { get; set; }
public DbSet<Behavior> Behaviors { get; set; }
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
base.OnModelCreating(modelBuilder);
modelBuilder.Conventions.Remove<OneToManyCascadeDeleteConvention>();
modelBuilder.Entity<SomeClass>()
.HasOptional(s => s.Behavior)
.WithRequired()
.WillCascadeOnDelete(true);
}
}
Now this code can be executed to demonstrate the point
(described with comments in the code below)
using(TestContext db = new TestContext())
{
var someClass = new SomeClass() { Name = "A" };
someClass.Behavior = new BehaviorA() { BehaviorASpecific = "Behavior A" };
db.SomeClasses.Add(someClass);
// Here I have two classes with the state of added which make sense
var modifiedEntities = db.ChangeTracker.Entries()
.Where(entity => entity.State != System.Data.Entity.EntityState.Unchanged).ToList();
// They save with no problem
db.SaveChanges();
// Now I want to change the behavior and it causes entity to try to remove the behavior and add it again
someClass.Behavior = new BehaviorB() { BehaviorBSpecific = "Behavior B" };
// Here it can be seen that we have a behavior A with the state of deleted and
// behavior B with the state of added
modifiedEntities = db.ChangeTracker.Entries()
.Where(entity => entity.State != System.Data.Entity.EntityState.Unchanged).ToList();
// But in reality when entity sends the query to the database it replaces the
// remove and insert with an update query (this can be seen in the SQL Profiler)
// which causes the discrimenator to remain the same where it should change.
db.SaveChanges();
}
How to change this entity behavior so that delete and insert happens instead of the update?
A possible solution is to make the changes in 2 different steps: before someClass.Behavior = new BehaviorB() { BehaviorBSpecific = "Behavior B" }; insert
someClass.Behaviour = null;
db.SaveChanges();
The behaviour is related to the database model. BehaviourA and B in EF are related to the same EntityRecordInfo and has the same EntitySet (Behaviors).
You have the same behaviour also if you create 2 different DbSets on the context because the DB model remains the same.
EDIT
Another way to achieve a similar result of 1-1 relationship is using ComplexType. They works also with inheritance.
Here an example
public class TestContext : DbContext
{
public TestContext(DbConnection connection) : base(connection, true) { }
public DbSet<Friend> Friends { get; set; }
public DbSet<LessThanFriend> LessThanFriends { get; set; }
}
public class Friend
{
public Friend()
{Address = new FullAddress();}
public int Id { get; set; }
public string Name { get; set; }
public FullAddress Address { get; set; }
}
public class LessThanFriend
{
public LessThanFriend()
{Address = new CityAddress();}
public int Id { get; set; }
public string Name { get; set; }
public CityAddress Address { get; set; }
}
[ComplexType]
public class CityAddress
{
public string Cap { get; set; }
public string City { get; set; }
}
[ComplexType]
public class FullAddress : CityAddress
{
public string Street { get; set; }
}
I am in an MVC4 application and i am using EF CodeFirst.
When I try to run the following code:
public void Autorizare(int cerereId, Persoana persoana)
{
var cerere = _db.Cereri.Find(cerereId);
cerere.Autorizare.Add(persoana);
_db.SaveChanges();
}
I get an error like this:
Entities in 'CerereDbContext.Persoane' participate in the 'Actiune_Executanti' relationship. 0 related 'Actiune_Executanti_Source' were found. 1 'Actiune_Executanti_Source' is expected.
i have tried Entity(Actiune).State = EntityState.Modified, but no results.
I have a main POCO:
public class Cerere
{
public int Id { get; set; }
...
public virtual ICollection<Actiune> Actiuni { get; set; }
...
}
the Actiune class looks like this
public class Actiune
{
public int Id { get; set; }
public DateTime Data { get; set; }
public String Nume { get; set; }
public virtual ICollection<Persoana> Executanti { get; set; }
public String Stadiu { get; set; }
public String Obs { get; set; }
}
And Persoana:
public class Persoana
{
public int Id { get; set; }
public DateTime Data { get; set; }
public String Nume { get; set; }
}
From your model the Cerere does not have a property named Autorizare; however it does have one named Actiuni. Which is of type Actiune not Persoana which is what you are trying to add to it. Please post the rest of the Class Definition.