This question already has answers here:
EF Core returns null relations until direct access
(2 answers)
Closed 4 years ago.
So I have 3 classes:
public class OwnerDto
{
public int Id { get; set; }
public string Name { get; set; }
public string EmailAddress { get; set; }
}
public class SitterDto
{
public int Id { get; set; }
public string Name { get; set; }
public string EmailAddress { get; set; }
}
public class ReviewDto
{
public int Id { get; set; }
public int Rating { get; set; }
//[ForeignKey("OwnerId")]
public OwnerDto Owner { get; set; }
//[ForeignKey("SitterId")]
public SitterDto Sitter { get; set; }
}
But I can't figure out how to do the proper modelBuilder. Everything I tried fails :( I am learning so bear with me.
My closest attempt was this:
modelBuilder.Entity<ReviewDto>()
.HasOne(t => t.Owner).WithMany().HasForeignKey("OwnerId");
Basically Owner and Sitter are always null :( Should i keep the [ForeignKey()] stuff or should i use a different extension method?
Declare all classes with navigation properties to each other. Mark one of the tables (the dependent table) with the ForeignKey attribute on its Primary Key.
EF infers one-to-many from this:
public class OwnerDto
{
public int Id { get; set; }
public string Name { get; set; }
public string EmailAddress { get; set; }
public ICollection<ReviewDto> Reviewers{ get; set; }
public ICollection<SitterDto> Sitters{ get; set; }
}
public class SitterDto
{
public int Id { get; set; }
public string Name { get; set; }
public string EmailAddress { get; set; }
public int OwnerId{ get; set; }
[ForeignKey("OwnerId")]
public OwnerDto Owner { get; set; }
}
public class ReviewDto
{
public int Id { get; set; }
public int Rating { get; set; }
public int OwnerId{ get; set; }
[ForeignKey("OwnerId")]
public OwnerDto Owner { get; set; }
}
and EF infers one-to-one from this:
public class OwnerDto
{
...
public ReviewDto Review{ get; set; }
...
}
public class ReviewDto
{
[ForeignKey("Owner")]
public int OwnerId { get; set; }
public OwnerDto Owner{ get; set; }
...
}
You need to refer Eager Loading in this scenario, You can use the Include method to specify related data to be includethe d in query results.
var query = from review in context.Review.Include(o => o.Owner).Include(s=>s.Sitter) select review;
My EF Code First model for some reason is not in sync with the db. I'm getting this error:
{"Invalid column name 'Type_Id1'."}
The field is actually called 'Type_Id' so I'm not sure from where that 1 comes up. I have the table column called as Type_Id and also I've added a Type_Id in my type entity model.
Why might I be getting that error message, plus why I'm getting 1 at the end of the name?
Update
My Task class:
public class Task
{
public Task()
{
Language = 1;
Grades = new HashSet<Grade>();
Categories = new HashSet<Category>();
Subjects = new HashSet<Subject>();
Rooms = new Collection<Room>();
Tools = new Collection<Tool>();
}
[Key]
public int Id { get; set; }
public string Description { get; set; }
public virtual TaskType Type { get; set; }
public string Rules { get; set; }
[Required]
[StringLength(200), MinLength(1)]
public string Name { get; set; }
public int PreperationTime { get; set; }
public int InstructionTime { get; set; }
public int TaskTime { get; set; }
public int Type_Id { get; set; }
public string VideoLink { get; set; }
[Required]
public int Language { get; set; }
public int? MinimumParticipants { get; set; }
public int? MaximumParticipants { get; set; }
public int? Rating { get; set; }
[Required]
public string CreatedBy { get; set; }
public virtual ICollection<Grade> Grades { get; set; }
public virtual ICollection<Category> Categories { get; set; }
public virtual ICollection<Subject> Subjects { get; set; }
public virtual ICollection<Room> Rooms { get; set; }
public virtual ICollection<Tool> Tools { get; set; }
}
DBContext class:
public ApplicationDbContext() : base("DefaultConnection", false)
{
}
public DbSet<Task> Tasks { get; set; }
public DbSet<TaskType> TaskTypes { get; set; }
public static ApplicationDbContext Create()
{
return new ApplicationDbContext();
}
You need to add the FK attribute on your navigation property. EF is creating Type_Id1 because Type_Id already exists (although it can't tell by convention it is the FK).
[ForeignKey("Type_Id")]
public virtual TaskType Type { get; set; }
https://msdn.microsoft.com/en-us/data/jj591583.aspx#Relationships
Using EntityFramework 6.1.3, I've got the following
public class RacesContext:DbContext
{
public DbSet<Race> Races { get; set; }
public DbSet<Sailboat> Sailboats { get; set; }
public DbSet<VenueParticipation> VenueParticipations { get; set; }
}
public class Crew
{
public int CrewId { get; set; }
public string Name { get; set; }
}
public class Sailboat
{
[Key]
public int SailboatId { get; set; }
public string Name { get; set; }
public string Skipper { get; set; }
public virtual ICollection<Crew> BoatCrew { get; set; }
}
public class VenueParticipation
{
[Key]
public int Id { get; set; }
public virtual ICollection<Sailboat> Boats { get; set; }
public virtual ICollection<Race> Races { get; set; }
}
public class Race
{
[Key]
public int RaceId { get; set; }
public string Venue { get; set; }
public DateTime Occurs { get; set; }
}
EF creates the Creates the Crews table with the proper PK and FK as I would expect. But creates the Races Sailboats, VenueParticipations tables in an unexpected way. Sailboats get's the expected PK but the unexpected FK VenueParticipation_Id as does Races. I was expecting the VenueParticipations table to get FKs to the others allowing a many to many relationship.. I'm sure I'm missing something here. Any advice would be great.
You can either configure the joining tables VenueParticipationSailboat, VenueParticipationRace with the proper FKs or you can use the fluent API:
modelBuilder.Entity<VenueParticipation>()
.HasMany(t => t.Sailboats)
.WithMany(t => t.VenueParticipations)
.Map(m =>
{
m.ToTable("VenueParticipationSailboat");
m.MapLeftKey("VenueParticipationID");
m.MapRightKey("SailboatID");
});
https://msdn.microsoft.com/en-us/data/jj591620.aspx#ManyToMany
I’m pretty new to EF and I have a little problem.
I just want to delete an item in my database. I’m using SQL Server 2012 Express, VS2012, AdventureWorks 2012.
The query that I execute is the following:
context = new AWEntities();
var removedItem = context.Addresses
.Include("StateProvince")
.Include("SalesOrderHeaders")
.Include("BusinessEntityAddresses").Single(d => d.AddressID == 11);
context.Addresses.Remove(removedItem);
context.SaveChanges();
The error that I get is
The DELETE statement conflicted with the REFERENCE constraint "FK_SalesOrderHeader_Address_ShipToAddressID". The conflict occurred in database "AdventureWorks2012", table "Sales.SalesOrderHeader", column 'ShipToAddressID'.
The statement has been terminated.
Is this actually a good way to delete items and the according entries in the other tables?
Please point me into the right direction.
public partial class Address
{
public Address()
{
this.BusinessEntityAddresses = new HashSet<BusinessEntityAddress>();
this.SalesOrderHeaders = new HashSet<SalesOrderHeader>();
}
public int AddressID { get; set; }
public string AddressLine1 { get; set; }
public string AddressLine2 { get; set; }
public string City { get; set; }
public int StateProvinceID { get; set; }
public string PostalCode { get; set; }
public System.Data.Spatial.DbGeography SpatialLocation { get; set; }
public System.Guid rowguid { get; set; }
public System.DateTime ModifiedDate { get; set; }
public virtual StateProvince StateProvince { get; set; }
public virtual ICollection<BusinessEntityAddress> BusinessEntityAddresses { get; set; }
public virtual ICollection<SalesOrderHeader> SalesOrderHeaders { get; set; }
}
public partial class StateProvince
{
public StateProvince()
{
this.Addresses = new HashSet<Address>();
this.SalesTaxRates = new HashSet<SalesTaxRate>();
}
public int StateProvinceID { get; set; }
public string StateProvinceCode { get; set; }
public string CountryRegionCode { get; set; }
public bool IsOnlyStateProvinceFlag { get; set; }
public string Name { get; set; }
public int TerritoryID { get; set; }
public System.Guid rowguid { get; set; }
public System.DateTime ModifiedDate { get; set; }
public virtual ICollection<Address> Addresses { get; set; }
public virtual CountryRegion CountryRegion { get; set; }
public virtual ICollection<SalesTaxRate> SalesTaxRates { get; set; }
public virtual SalesTerritory SalesTerritory { get; set; }
}
}
public partial class BusinessEntityAddress
{
public int BusinessEntityID { get; set; }
public int AddressID { get; set; }
public int AddressTypeID { get; set; }
public System.Guid rowguid { get; set; }
public System.DateTime ModifiedDate { get; set; }
public virtual Address Address { get; set; }
public virtual AddressType AddressType { get; set; }
public virtual BusinessEntity BusinessEntity { get; set; }
}
public partial class SalesOrderHeader
{
public SalesOrderHeader()
{
this.SalesOrderDetails = new HashSet<SalesOrderDetail>();
this.SalesOrderHeaderSalesReasons = new HashSet<SalesOrderHeaderSalesReason>();
}
public int SalesOrderID { get; set; }
public byte RevisionNumber { get; set; }
public System.DateTime OrderDate { get; set; }
public System.DateTime DueDate { get; set; }
public Nullable<System.DateTime> ShipDate { get; set; }
public byte Status { get; set; }
public bool OnlineOrderFlag { get; set; }
public string SalesOrderNumber { get; set; }
public string PurchaseOrderNumber { get; set; }
public string AccountNumber { get; set; }
public int CustomerID { get; set; }
public Nullable<int> SalesPersonID { get; set; }
public Nullable<int> TerritoryID { get; set; }
public int BillToAddressID { get; set; }
public int ShipToAddressID { get; set; }
public int ShipMethodID { get; set; }
public Nullable<int> CreditCardID { get; set; }
public string CreditCardApprovalCode { get; set; }
public Nullable<int> CurrencyRateID { get; set; }
public decimal SubTotal { get; set; }
public decimal TaxAmt { get; set; }
public decimal Freight { get; set; }
public decimal TotalDue { get; set; }
public string Comment { get; set; }
public System.Guid rowguid { get; set; }
public System.DateTime ModifiedDate { get; set; }
public virtual Address Address { get; set; }
public virtual ShipMethod ShipMethod { get; set; }
public virtual CreditCard CreditCard { get; set; }
public virtual CurrencyRate CurrencyRate { get; set; }
public virtual Customer Customer { get; set; }
public virtual ICollection<SalesOrderDetail> SalesOrderDetails { get; set; }
public virtual SalesPerson SalesPerson { get; set; }
public virtual SalesTerritory SalesTerritory { get; set; }
public virtual ICollection<SalesOrderHeaderSalesReason> SalesOrderHeaderSalesReasons { get; set; }
}
Can't really tell much from what you have said, but you may benefit from looking into using the DbModelBuilder to solve cascade issues:
modelBuilder.Entity<Parent>()
.HasMany<Child>(c => c.Children)
.WithOptional(x => x.Parent)
.WillCascadeOnDelete(true);
Again, would need more information about your model structure to determine if this is the right approach.
Either that or in your delete method, remove any children first, and then remove the parent.
modelBuilder.Entity<Parent>()
.HasMany<Child>(c => c.Children)
.WithOptional(x => x.Parent)
.WillCascadeOnDelete(true);
or use Include
var adv = db.Adv.Include(b => b.Features)
.Include(b => b.AdvDetails)
.Include(b => b.AdvGallery)
.FirstOrDefault(b => b.Id == id);
db.Adv.Remove(adv);
for .HasMany(...).WithMany(...) Include is ok
You can resolve this issue on SQL side
Method 1 :
First, you need to find on which table this FK constraint has been defined, through using Replication monitor.
Right click on that FK, click Modify, you should get popup box like one shown below.
From the popup box, Select Cascade for del.
Method 2 :
set ON DELETE CASCADE in sql at the end of constraint.
In EF Core the syntax in builder is as follows:
builder.HasOne(b => b.Parent )
.WithMany(a => a.Children)
.OnDelete(DeleteBehavior.Cascade);
https://learn.microsoft.com/en-us/ef/core/saving/cascade-delete
I got this error when I created Entity B, that referenced Entity A, and then tried to delete Entity A. SQL/EF did not allow me to leave that dangling Id reference, since the objcet no longer existed. Cascading deletes would solve this, but I wanted B to persist. So I have to remove the reference from B before deleting A:
var existingContractApprovers = _repo.Query<ChangeOrderApproverForContract>().Where(coafc => coafc.ContractId == key).ToList();
//remove refs to contract approvers to preserve data integrity
foreach(var contractApp in existingContractApprovers)
{
var associatedChangeOrderApprovers = _repo.Query<ChangeOrderApprover>().AsNoTracking().Where(coafc => coafc.ChangeOrderApproverForContractId == contractApp.Id).ToList();
foreach(var coApp in associatedChangeOrderApprovers)
{
_repo.Edit(coApp);
coApp.ChangeOrderApproverForContractId = null;
}
}
_repo.SaveChanges();
//remove the contract approvers
foreach (var contractApp in existingContractApprovers)
{
_repo.Delete(contractApp);
}
_repo.SaveChanges();
You can do this in EF Core.
modelBuilder.Entity<Parent>()
.HasMany<Child>(c => c.Children)
.WithOne(s => s.Parent)
.OnDelete(DeleteBehavior.Cascade);
The safer alternative is to make sure all children are deleted before deleting the parent. You should cascade on delete only if you are completely aware of how your entities relate. For example, you could have lots of orders connected to
a certain category in your e-commerce store. Once the category is deleted, all the orders and any entity whose foreign keys are connected to this parent category will be gone.
I'm trying to eager load some child entities like so:
_context.Sites.Where(x => x.ID == siteID).Include(s => s.SiteLoggers).FirstOrDefault();
However, the error I am getting is:
A specified Include path is not valid. The EntityType 'MyProject.Dal.EF.Site' does not declare a navigation property with the name 'SiteLoggers'.
What is saying is correct, as MyProject.Dal.EF.Site does not exist, the object exists in MyProject.Domain.Entities.Site
What am I missing??? Thanks!
POCOs:
namespace MyProject.Domain.Entities
{
public class Site
{
public int ID { get; set; }
public int LocationID { get; set; }
public bool Active { get; set; }
public bool Deleted { get; set; }
public string Name { get; set; }
public virtual Location Location { get; set; }
public virtual IEnumerable<SiteLogger> SiteLoggers { get; set; }
}
}
namespace MyProject.Domain.Entities
{
public class SiteLogger
{
public int ID { get; set; }
public int UID { get; set; }
public int SiteID { get; set; }
public string Name { get; set; }
public int LocationID { get; set; }
public bool Active { get; set; }
public bool Deleted { get; set; }
public virtual Site Site { get; set; }
public virtual Location Location { get; set; }
}
}
You need to use ICollection instead of IEnumerable, because EF requires that your navigation properties are defined as ICollection<T>.
public virtual ICollection <SiteLogger> SiteLoggers { get; set; }