I am getting the following error when trying to add a migration:
PS C:\Code\morpher.ru\Morpher.Database> dotnet ef migrations add AddQazaqFeatures --startup-project=../Morpher.Database.Design
Build started...
Build succeeded.
System.InvalidOperationException: The association between entity types 'Service' and 'Deployment' has been severed but the relationship is either m
arked as 'Required' or is implicitly required because the foreign key is not nullable. If the dependent/child entity should be deleted when a requi
red relationship is severed, then setup the relationship to use cascade deletes. Consider using 'DbContextOptionsBuilder.EnableSensitiveDataLoggin
g' to see the key values.
at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.InternalEntityEntry.HandleConceptualNulls(Boolean sensitiveLoggingEnabled, Boolean forc
e, Boolean isCascadeDelete)
at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.StateManager.CascadeDelete(InternalEntityEntry entry, Boolean force, IEnumerable`1 fore
ignKeys)
...
My code:
public class Deployment
{
public int Id { get; set; }
public virtual Service Service { get; set; }
public int ServiceId { get; set; }
public string Host { get; set; }
public short? Port { get; set; }
public string BasePath { get; set; }
}
public class Service
{
public int Id { get; set; }
public string Name { get; set; }
public string UrlSlug { get; set; }
public virtual ICollection<Endpoint> Endpoints { get; set; }
public virtual ICollection<Deployment> Deployments { get; set; }
}
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
modelBuilder.Entity<Service>().HasData(new Service
{
Name = "Веб-сервис «Морфер»",
UrlSlug = "ws",
Id = 1
});
modelBuilder.Entity<Deployment>().HasData(new Deployment
{
Host = "ws3.morpher.ru",
ServiceId = 1,
Id = 1
});
modelBuilder.Entity<Deployment>(entity =>
{
entity.Property(e => e.Host).IsRequired().HasMaxLength(256);
entity.Property(e => e.BasePath).HasMaxLength(512);
entity.HasOne(deployment => deployment.Service)
.WithMany(service => service.Deployments)
.HasForeignKey(d => d.ServiceId)
.OnDelete(DeleteBehavior.Restrict)
.HasConstraintName("FK_Deployments_Services");
});
}
There are numerous StackOverflow questions mentioning the same error (1, 2, 3), but they are mostly to do with removing entities while not having a CASCADE delete policy or a nullable foreign key.
In my case, I am trying to add new rows and I don't see why it is considering the relationship 'severed'. Is setting ServiceId = 1 not enough?
I was able to reproduce the issue in latest at this time EF Core 3.1 version (3.1.28) by first removing the model data seeding code (HasData calls), then adding migration for just creating the tables/relationships, then adding the data seeding code and attempting to add new migration.
It does not happen in latest EF Core 6.0, so apparently you are hitting EF Core 3.1 defect/bug which has been fixed somewhere down on the road. So you either need to upgrade to a newer EF Core version (with all associated burdens like retesting everything, breaking changes etc.), or use the workaround below.
The workaround is to replace the DeleteBehavior.Restrict with either ClientNoAction or NoAction. Values of that enum and documentation of what they do is kind of messy, but all these 3 values seem to generate one and the same regular enforced FK constraint (with no cascade) in the database, and differ only by client side behavior, or in other words, what does EF Core change tracker do with related tracked entities when "deleting" a principal entity. And in this particular case, `Restrict" throws exception when there are tracked (loaded) related entity instances, while the other two won't.
I know you think you are just "adding data", but EF Core model data seeding is more than that - it tries to keep that data, so in some circumstances it needs to update or delete previously added data. Which in general works, except when there are bugs in the EF Core codebase, like in this case.
Related
I am working on .NET CORE 6 along with EF CORE 7. I need to seed data in joining table but unable to do so and get error.
I am seed FileTypeId but not sure why EF core migration throwing error...
error
The seed entity for entity type 'JobFileType' cannot be added because it has the navigation 'FileType' set. To seed relationships, add the entity seed to 'JobFileType' and specify the foreign key values {'FileTypeId'}. Consider using 'DbContextOptionsBuilder.EnableSensitiveDataLogging' to see the involved property values.
ClassA
public class JobProfile
{
public JobProfile()
{
this.JobFileTypes = new HashSet<JobFileType>();
}
public Guid JobProfileId { get; set; }
public string Name { get; set; }
public ICollection<JobFileType>? JobFileTypes { get; set; }
}
ClassB
public class FileType
{
public FileType()
{
this.JobFileTypes = new HashSet<JobFileType>();
}
public Guid FileTypeId { get; set; }
public string Extension { get; set; } = string.Empty;
public ICollection<JobFileType>? JobFileTypes { get; set; }
}
Joing Table
public class JobFileType
{
public Guid JobFileTypeId { get; set; }
public Guid JobProfileId { get; set; }
public JobProfile JobProfile { get; set; } = new JobProfile();
public Guid FileTypeId { get; set; }
public FileType FileType { get; set; } = new FileType();
}
Seed Extension
public static class JobFileTypeSeed
{
public static void Seed(this ModelBuilder modelBuilder)
{
modelBuilder.Entity<JobFileType>()
.HasData(
new JobFileType {JobFileTypeId = Guid.Parse("aaa"), JobProfileId = Guid.Parse("ccc"), FileTypeId = Guid.Parse("yyy") },
new JobFileType { JobFileTypeId = Guid.Parse("bbb"), JobProfileId = Guid.Parse("ccc"), FileTypeId = Guid.Parse("zzz") }
);
}
}
config
internal class JobFileTypeConfiguration : IEntityTypeConfiguration<JobFileType>
{
public void Configure(EntityTypeBuilder<JobFileType> builder)
{
builder.ToTable("JobFileType", "dbo");
builder.HasKey(column => column.JobFileTypeId);
builder
.HasOne(jobFileType => jobFileType.JobProfile)
.WithMany(jobProfile => jobProfile.JobFileTypes)
.HasForeignKey(jobFileType => jobFileType.JobProfileId);
builder
.HasOne(jobFileType => jobFileType.FileType)
.WithMany(fileType => fileType.JobFileTypes)
.HasForeignKey(jobFileType => jobFileType.FileTypeId);
}
}
There is not much to say about the concrete issue (which btw is not specific to joining entity, but any entity model seeding):
I am seed FileTypeId but not sure why EF core migration throwing error...
as the cause of the issue is included at the beginning of the error message:
because it has the navigation 'FileType' set.
And your entity has
public FileType FileType { get; set; } = new FileType();
// ^ ^ ^
// the problem
and the same for
public JobProfile JobProfile { get; set; } = new JobProfile();
which will be the next error if you resolve the original.
Remove both navigation property initializers (= new ...) and the problem will be gone.
As a general rule, you should never initialize reference navigation properties because it causes many side effects and/or improper behaviors (not only for seeding, but also eager/lazy/explicit data loading). Initializing collection navigation properties is arbitrary, but ok. Only reference navigation property initialization must be avoided. For more info, see EF codefirst : Should I initialize navigation properties? - quite old EF topic, but still applies.
If you are trying to resolve NRT warnings (as I guess), initializing with new is definitely not a proper way. One reason I don't like NRT is because it is forcing people to use "workarounds" for preventing compiler warnings, which in fact break the primary functionality. Specifically in EF Core, enabling NRT also changes the optional/required attribute of some properties, hence database column types (most noticeable for string properties/columns and reference navigations). You could read more about this in the Working with Nullable Reference Types topic in the official EF Core documentation, but in general I would just disable NRT for EF entity model classes.
The proper order is to set the "master data" first and then try to set the join table, as you would expect.
The defaulting
{get;set;} = new Something();
Could be the offending declaration, since any instance upon creation will have the relation JobFileType already set
I have the following model:
public partial class Driver
{
public string FirstName { get; set; }
public string LastName { get; set; }
public string Nickname { get; set; }
public virtual AspNetUser AspNetUser { get; set; }
......
}
public partial class AspNetUser
{
public string Id { get; set; }
public string UserName { get; set; }
public virtual Driver Driver { get; set; }
......
}
and the following mapping:
this.HasOptional(c => c.Driver)
.WithOptionalPrincipal(a => a.AspNetUser)
.Map(m => m.MapKey("AspNetUserId"));
It creates correct DB model, adds nullable AspNetUserId FK to Driver table.
But how to link one object with another in code. I don't have AspNetUserId property, so, I try to set object, like this:
_db.Drivers.Attach(driver);
_db.AspNetUsers.Attach(aspNetUser);
driver.AspNetUser = aspNetUser;
_db.SaveChanges();
but then I got an exception :
"An error occurred while saving entities that do not expose foreign
key properties for their relationships. The EntityEntries property
will return null because a single entity cannot be identified as the
source of the exception. Handling of exceptions while saving can be
made easier by exposing foreign key properties in your entity types.
See the InnerException for details."
"Store update, insert, or delete statement affected an unexpected
number of rows (0). Entities may have been modified or deleted since
entities were loaded. See
http://go.microsoft.com/fwlink/?LinkId=472540 for information on
understanding and handling optimistic concurrency exceptions."
How to solve it with EF 6.X ?
This is happening when the Driver is already associated with AspNetUser. When you attach the driver with AspNetUser property being null, EF assumes the original value of AspNetUserId being null and generates update statement with AspNetUserId IS NULL additional criteria, which of course does not match the existing record, the command returns 0 records affected and EF generates the exception in question.
The solution is (1) to load the original Driver.AspNetUser property value from the database before setting the new value. Also, in order to correctly handle the case when the new AspNetUser is already associated with a different Driver, you should (2) load AspNetUser.Driver property as well:
_db.Drivers.Attach(driver);
_db.AspNetUsers.Attach(aspNetUser);
_db.Entry(driver).Reference(e => e.AspNetUser).Load(); // (1)
_db.Entry(aspNetUser).Reference(e => e.Driver).Load(); // (2)
driver.AspNetUser = aspNetUser;
_db.SaveChanges();
I am absolutely stumped in trying to figure out how to implement a bi-directional 1..n relationship in Entity Framework using Code First. For example, a team (represented by a Team entity) has a coach and a manager (both represented by a Person entity). So, my Team model could be as follows:
public class Team
{
public Team()
{
Manager = new Person();
Coach = new Person();
}
[Key, DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int TeamID { get; set; }
public string Name { get; set; }
[ForeignKey("Manager")]
public int ManagerID { get; set; }
public virtual Person Manager { get; set; }
[ForeignKey("Coach")]
public int CoachID { get; set; }
public virtual Person Coach { get; set; }
}
I can implement one-way navigation by implementing the Person Entity as follows:
public class Person
{
[Key, DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int PersonID { get; set; }
public string Name { get; set; }
}
and the fluent API:
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Entity<Team>()
.HasRequired(t => t.Manager);
modelBuilder.Entity<Team>()
.HasRequired(t => t.Coach);
base.OnModelCreating(modelBuilder);
}
However, while that allows me to navigate from the Team entity to the related Coach and Manager (both instances of Person), it doesn't allow me to directly navigate from the Coach or Manager to the related Team. So, to implement 2-way navigation, I modified the Person entity as follows:
public class Person
{
[Key, DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int PersonID { get; set; }
public string Name { get; set; }
[ForeignKey("Team")]
public int TeamID { get; set; }
public virtual Team Team { get; set; }
}
While that builds ok, I get the following runtime error when I try to save to the database:
System.Data.Entity.Core.UpdateException
InnerException: Unable to determine a valid ordering for dependent operations. Dependencies may exist due to foreign key constraints, model requirements, or store-generated values.
So, to specify the ordering between the entities, I tried to modify the fluent API by adding the "WithRequiredPricipal" as follows:
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Entity<Team>()
.HasRequired(t => t.Manager)
.WithRequiredPrincipal(t => t.Team);
modelBuilder.Entity<Team>()
.HasRequired(t => t.Coach)
.WithRequiredPrincipal(t => t.Team);
base.OnModelCreating(modelBuilder);
}
However, when I attempt to execute "add-migration" in the Package Manager Console, I get the following error:
System.InvalidOperationException: The navigation property 'Team' declared on type 'RelatedEntities.Models.Person' has been configured with conflicting foreign keys.
What I'm attempting to achieve seems like a straightforward requirement but I've done heaps of searching for a solution without yet finding an answer. Am I missing something in the fluent API or the annotations?
(I don't want to implement a workaround, such as implementing separate models for Coach and Manager because a team may have numerous other roles (eg, Assistant Coach, Public Relations Manager, etc). I would want each to simply be an instance of a Person entity.)
You didn't define your foreign key constraints.
.HasRequired(t => t.Manager)
.WithMany()
.HasForeignKey(t => t.ManagerId)
As a side note. If your manager was managing multiple teams the WithMany would be .WithMany(m => m.Teams) and your manager model would need something like this:
private ICollection<Team> _teams
public ICollection<Team> Teams
{
get { return _teams ?? (teams = new List<Team>()); }
protected set { _teams = value; }
}
Sorry for formatting. On my phone. Good luck.
Ok, I can now answer my own question in case anyone else encounters the same problem.
Firstly, as I mention in my comment above, the problem that I described in my question turns out to be a recognized shortcoming in Entity Framework that the EF Triage Team has flagged to be addressed in a future release of EF.
In the meantime, the workaround that has been suggested by a number of contributors in response to questions about how to implement circular dependencies in EF (which is what my example above is trying to do) is to do it in stages as follows:
Create the principal entity
Call SaveChanges() on DbContext
Create the dependent entity and set the foreign key before calling SaveChanges() again (at some subsequent point)
So, using the Team example in my original question above, instead of creating the dependent Manager and Coach entities in the Team constructor, the first change was to make the Team's foreign keys to the Coach and Manager optional (instead of required), so that the Team could be instantiated without the Coach and Manager, and then call SaveChanges():
Team team = Teams.Add(new Team());
SaveChanges();
After that, I then create the dependent Manager and Coach entities and set their foreign keys to the ID of the Team instance:
team.Manager = new Person();
team.Manager.TeamID = team.TeamID;
team.Coach = new Person();
team.Coach.TeamID = team.TeamID;
At any time after that, SaveChanges() can be called without causing a runtime error as previously.
When this issue is addressed in a future release of EF, it should be possible to create the principal and dependent entities without having to call SaveChanges() in between.
When using Entity Framework Code First 4.3.1 it is possible to create relationships with a multiplicity of 1-to-1. That is, one entity on each end of the relationship.
It is possible to configure 1-to-1 relationships to be required-required or required-optional ^. However, when I switch between the two I do not see any differences in:
The database schema generated. I am targeting SQL Server 2008.
The runtime behaviour of EF.
As such, I am able to create a RequiredPrincipalAs record without a corresponding RequiredDependentAs record, despite the relationship being configured as required-required. This seems to contradict the documentation for HasRequired(...):
Configures a required relationship from this entity type. Instances of the entity type will not be able to be saved to the database unless this relationship is specified. The foreign key in the database will be non-nullable.
http://msdn.microsoft.com/en-us/library/gg671317
The required-required relationship entities:
public class RequiredPrincipalA
{
public int Id { get; set; }
public virtual RequiredDependentA DependentA { get; set; }
}
public class RequiredDependentA
{
public int Id { get; set; }
public virtual RequiredPrincipalA PrincipalA { get; set; }
}
The required-optional relationship entities:
public class RequiredPrincipalB
{
public int Id { get; set; }
public virtual OptionalDependentB DependentB { get; set; }
}
public class OptionalDependentB
{
public int Id { get; set; }
public virtual RequiredPrincipalB PrincipalB { get; set; }
}
The DbContext and model configuration:
public class AppContext : DbContext
{
public DbSet<RequiredPrincipalA> PrincipalAs { get; set; }
public DbSet<RequiredDependentA> DependentAs { get; set; }
public DbSet<RequiredPrincipalB> PrincipalBs { get; set; }
public DbSet<OptionalDependentB> DependentBs { get; set; }
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Entity<RequiredPrincipalA>()
.HasRequired(o => o.DependentA)
.WithRequiredPrincipal(o => o.PrincipalA);
modelBuilder.Entity<RequiredPrincipalB>()
.HasOptional(o => o.DependentB)
.WithRequired(o => o.PrincipalB);
}
}
The test code:
Database.SetInitializer(new DropCreateDatabaseAlways<AppContext>());
using (var ctx = new AppContext())
{
ctx.Database.Initialize(force: false);
ctx.PrincipalAs.Add(new RequiredPrincipalA());
ctx.PrincipalBs.Add(new RequiredPrincipalB());
ctx.SaveChanges();
}
I am aware I could add a [Required] data attribute to the navigation properties of RequiredPrincipalA.DependentA and RequiredDependentA.PrincipalA. This would cause EF validation to prevent the scenario above. However, I do not want to do this because it also validates the navigation property is populated when updating an existing entity. This means the application has to pre-fetch the entity at the other end of the relationship for every update.
Why do I not see any difference in the behaviour of EF just when changing a relationship between required-required and required-optional?
^ Note that optional-optional is also supported but this doesn't form part of my question. There are obvious differences in the generated database schema and runtime behaviour when an optional-optional relationship is configured.
I don't know why required-required is allowed for this case but it cannot exist in the database because relation is build on primary keys. Required-required means that A cannot be inserted if related B doesn't exist and B cannot be inserted if related A doesn't exist => neither A or B can be inserted.
Database relation has always principal and dependent entity - principal can always exist without dependent.
Real required-required in EF can be achieved only when both A and B are mapped to the same table (table splitting) because in such case they are both inserted with single insert command.
Not really an answer but I have more to say than will fit in comments. But you know, I write 900 page books...it's just how I roll. :)
Oddly I would expect the fluent configuration to behave the same way as the data annotation and am confused that it's not doing it. (I've pinged Rowan Miller with a link to this thread to get his feedback.) And the behavior I mean is: validating the constraint during SaveChanges.
On the database side, I'm with Ladislav.In the model, EF defines the 1:1 using the keys of the related entities. But in the database, you can't have FKs in both tables, so only the dependent table in the database will require that constraint that it's PK maps to an existing PK in the principal table.
And finally, I understand your reason for not wanting EF to enforce the relationship if you aren't going to always deal with teh full graph. I think 1:1 relationships are the most confusing of the EF relationship mappings and I always find myself having to go back for reminders of the rules and how things should work.
Old question. But since EF6 is still used and even available for .Net standard and this issue can be a real nuisance, I think it's worth mentioning something I couldn't find in other answers.
It is true that both HasRequired - WithRequiredPrincipal and HasOptional - WithRequired produce the same database schema and the same runtime behavior. That is, with both mappings it's possible to save a principal without a dependent entity and to remove the dependent later. So much for HasRequired.
But there is a way to make EF validate the required relationship when creating the entities, which is by simply adding a [Required] attribute:
public class RequiredPrincipalA
{
public int Id { get; set; }
[Required] // <== here
public virtual RequiredDependentA DependentA { get; set; }
}
public class RequiredDependentA
{
public int Id { get; set; }
public virtual RequiredPrincipalA PrincipalA { get; set; }
}
As said, only when creating the entities. It's still possible to set RequiredPrincipalA.RequiredDependentA = null and save it successfully. But I think that, fortunately, the likelihood of that happening in code is far lower than forgetting to set the required dependent.
Say I have Project and Task EF Code first classes
public class Project
{
public int ID { get; set; }
public string Name { get; set; }
public virtual ICollection<Task> Tasks { get; set; }
}
public class Task
{
public int ID { get; set; }
public string Name { get; set; }
public int ProjectId { get; set; }
public bool IsDeleted {get; set;}
public virtual Project Project { get; set; }
}
Say I have
public void SomeAction()
{
Project p= repository.GetById(1);
var tasks = p.Tasks;
//var tasks = p.Tasks.Where(t=>t.IsDeleted==false);
}
I would like that my Tasks property on the Project class will always perform that filter on IsDeleted and just return that subset ... to avoid having to write that condition all over the place...
Any recommendations?
Edit:
Im using EF Code First
Add a discriminator to your model in the OnModelCreating method
modelBuilder.Entity<TEntity>().Map(m => m.Requires("IsDeleted").HasValue(false));
Caveats
You can no longer load deleted items (unless you map IsDeleted true to another entity, then you may lose your automatic filtering)
The poco class cannot have the IsDeleted property (discriminators cannot be mapped)
because the IsDeleted cannot be mapped you need to run raw SQL to delete the entity in the first place.
EF Code first = NO WAY. Just one from long list of features which is available in EDMX and it is completely missing in code first. Mapped condition from EDMX does this but it is still problematic because it is hardcoded and cannot be changed (= you will never be able to load deleted entities even if you want to unless you use another EDMX). The solution would be implementation of global filters in EF but EF doesn't have anything like that despite the fact that old Linq-to-entities have them at least for relations (DataLoadOptions.AssociateWith).
This is much more painful in relations where you cannot use eager or lazy loading without loading deleted entities to your application as well and do filtering in your application's memory.
In the Model Designer, select your Task entity, and bring up the Mapping Details window. This should show you the database table your entity is mapped to, and all the columns. Just under where it says "Maps to [YourTable]" you should see an option <Add a Condition>. This should let you set a condition like what you're looking for.