Before the migration I had an 1 to many relationship between tables Work and Factory:
public class Work
{
public int WorkId { get; set; }
public string Name { get; set; }
public virtual List<Factory> MyFactory { get; set; }
}
and:
public class Factory
{
public int FactoryId { get; set; }
public string Name { get; set; }
public virtual Work ParentWork { get; set; }
}
Then I tried to change the relationship to be an 1 to 1:
public class Work
{
public int WorkId { get; set; }
public string Name { get; set; }
[Required]
public virtual Factory MyFactory { get; set; }
}
public class Factory
{
public int FactoryId { get; set; }
public string Name { get; set; }
public virtual Work ParentWork { get; set; }
}
When I tried to create the migration with:
add-migration MyMigration
I received the following error:
The ALTER TABLE statement conflicted with the FOREIGN KEY constraint "FK_dbo.Work_dbo.Factory_WorkId". The conflict occurred in database "EntityFrameworkLab.MyContext", table "dbo.Factory", column 'FactoryId'
Now, I have a few questions:
1) Why couldn't the migration be created, whereas the model is valid?
2) What changes should I implement in the code?
3) If I try to manually revert the changes, the same error message occurs, but this time when I try to do the:
update-database -verbose
Related
I'm using E.F 6.2 code first in my MVC project and configure the project for using Asp.Net Identity 2 for accounting. I have a "BaseData" entity, that contains all of my basic data. Here is the class body:
Parent Entity:
public class BaseData
{
public int Id { get; set; }
public string Caption { get; set; }
public virtual ICollection<A> Children1 { get; set; }
public virtual ICollection<B> Children2 { get; set; }
.
.
.
public virtual ICollection<ZZZ> ChildrenN { get; set; }
}
So the other entities must be related to it. In my case, each child entity has hundreds of relations to the "BaseData" parent entity and I have hundreds of child entities. So there is thousands of relations to the parent entity. Here is the pseudo code for child entities:
Child Entities:
public class A
{
public int Id { get; set; }
public int BaseData1Id { get; set; }
public BaseData BaseData1 { get; set; }
public int BaseData2Id { get; set; }
public BaseData BaseData2 { get; set; }
.
.
.
public int BaseData300Id { get; set; }
public BaseData BaseData300 { get; set; }
}
.
.
.
.
public class ZZZ
{
public int Id { get; set; }
public int BaseData1Id { get; set; }
public BaseData BaseData1 { get; set; }
public int BaseData2Id { get; set; }
public BaseData BaseData2 { get; set; }
.
.
.
public int BaseData300Id { get; set; }
public BaseData BaseData300 { get; set; }
}
I'm using E.F fluent API to configure the relationship between my entities. The problem is that when I run the project and want to fetch some data like user account, I get the "StackOverFlow" exception !!
For solving the problem, I try to remove child entities one by one, and re-creating the database. I found that when the children decreases, the problem is solved and I didn't get exception but I don't know really why !!
Is there limitation for navigation properties on E.F ?
Is there a solution to increase the stack capacity for preventing "StackOverFlow" exception ?
I have a .Net Core 2 webapi in which I am using automapper to map to Dtos. Everything works fine, except I am seeing an unexpected behaviour when I map an object to a Dto, and where the Dto also contains mappings for a collection. E.g
CreateMap<Order, OrderDto>();
CreateMap<Product, ProductDto>();
Where classes are like this
public partial class Order
{
public int Id { get; set; }
public string Name { get; set; }
public virtual ICollection<Product> Products{ get; set; }
public int ProductCount {return Products.Count;}
}
public partial class Product
{
public int Id { get; set; }
public int OrderId { get; set; }
public string Name { get; set; }
public string Description { get; set; }
}
The following works as expected;
The class is mapped, and the ProjectCount is correct in the Dto
public partial class OrderDto
{
public int Id { get; set; }
public virtual ICollection<Product> Products{ get; set; }
public int ProductCount{ get; set; }
}
_context.Orders.Include<>(Products).ProjectTo<>(OrderDto)
But doing the following, the productcount is always zero.
E.g. if I do this;
public partial class OrderDto
{
public int Id { get; set; }
public virtual ICollection<ProductDto> Products{ get; set; }
public int ProductCount{ get; set; }
}
public partial class ProductDto
{
public int Id { get; set; }
public int OrderId { get; set; }
public string Name { get; set; }
}
_context.Orders.Include<>(Products).ProjectTo<>(OrderDto)
Why does this happen, and how can I ensure that it doesnt? This is a real world example where I need a property which references the collection - and I need it in both the base and the Dto. I can do the following which works fine, but it doesnt appear that this should be how it works...
public partial class OrderDto
{
public int Id { get; set; }
public virtual ICollection<ProductDto> Products{ get; set; }
public int ProductCount {return Products.Count;}
}
public partial class ProductDto
{
public int Id { get; set; }
public string Name { get; set; }
}
_context.Orders.Include<>(Products).ProjectTo<>(OrderDto)
I profiled the SQL and found that Automapper changes the way the query is formed. Without the nested projection, two queries are made;
[Queries are more complex than this and use joins, but you get the idea]
Select Id from orders
Select Id,Name from products where productid in [select id from orders ]
With the nested projection, are executed for each nested Dto
Select Id from orders
Select Id,Name from products where id=1
Select Id,Name from products where id=2
I am trying to implement DbContext for couple of tables called 'Employee' and 'Department'
Relationship between Employee and Department is many to one. i.e. department can have many employees.
Below are the EntityFramework classes I designed ( CodeFirst approach )
[Table("Employee")]
public class Employee
{
[DatabaseGenerated(System.ComponentModel.DataAnnotations.Schema.DatabaseGeneratedOption.Identity)]
public int Id { get; set; }
[Column("Name")]
public string Name { get; set; }
[Column("Department_ID")]
public int Department_ID { get; set; }
public virtual Department Department { get; set; }
}
[Table("Department")]
public class Department
{
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int ID { get; set; }
[Column("Name")]
public string Name { get; set; }
public virtual ICollection<Employee> Employees { get; set; }
}
While adding Employee record I am getting below exception
"Invalid column name 'Department_ID1'."
I am not sure why EF is referring to Department_ID1. Do I need to add configuration in OnModelCreating method of DbContext?
I am using EF version 6.1.1
I've also gotten this problem in my EF one-many deals where the one has a List of the many property and my mapping didn't specify that property. For example take:
public class Notification
{
public long ID { get; set; }
public IList<NotificationRecipient> Recipients { get; set; }
}
then
public class NotificationRecipient
{
public long ID { get; set; }
public long NotificationID { get; set; }
public Notification Notification { get; set; }
}
Then in my mapping, the way that caused the Exception (the incorrect way):
builder.HasOne(x => x.Notification).WithMany()
.HasForeignKey(x => x.NotificationID);
What fixed it (the correct way) was specifying the WithMany property:
builder.HasOne(x => x.Notification).WithMany(x => x.Recipients)
.HasForeignKey(x => x.NotificationID);
Hi After spending some time I could fix this problem by using ForeignKey attribute on public virtual Department Department { get; set; } property of Employee class.
Please see below code.
[Table("Employee")]
public class Employee
{
[DatabaseGenerated(System.ComponentModel.DataAnnotations.Schema.DatabaseGeneratedOption.Identity)]
public int Id { get; set; }
[Column("Name")]
public string Name { get; set; }
[Column("Department_ID")]
public int Department_ID { get; set; }
[ForeignKey("Department_ID")]
public virtual Department Department { get; set; }
}
This fixed my problem. Are there any other solution to fix this? Using fluent API?
For me, the issue was resolved by removing a (duplicate?) virtual property.
Using the OP's example:
public class Employee
{
public int Id { get; set; }
public string Name { get; set; }
public int Department_ID { get; set; }
public virtual Department Department { get; set; }
}
public class Department
{
public int ID { get; set; }
public string Name { get; set; }
public virtual ICollection<Employee> Employees { get; set; }
}
Turns into:
public class Employee
{
public int Id { get; set; }
public string Name { get; set; }
public int Department_ID { get; set; }
}
public class Department
{
public int ID { get; set; }
public string Name { get; set; }
public virtual ICollection<Employee> Employees { get; set; }
}
In my case I added a virtual property on top of the auto generated property
I fixed it by adding the NotMapped attribute to my property, or you could configure with fluent api
public partial class Control
{
[NotMapped]
public virtual ICollection<Control> Children { get => this.InverseParent; set => this.InverseParent = value; }
}
I had the same error, my issue was the FK was a long but I had it as an int in the model. EF generated a new column because it didn't match types on the FK so it assumed they weren't the same and went ahead with making another one but putting 1 at the end because there was already one with the proper name. Making sure the types matched resolved the issue for me.
This can be fixed simply by putting [NotMapped] annotation on your virtual properties.
public class Employee
{
[ForeignKey("Department")]
public int Department_ID
[NotMapped]
public virtual Department Department { get; set; }
}
And in you modelBuilder:
modelBuilder.Entity<Employee>(entity =>
{
entity.HasOne(e => e.Department);
});
Just flip this around if you want to call by Department.
We use the [NotMapped] annotation so that EF Core will disregard it when looking at your database.
In .NET 4.0 framework the System.ComponentModel.DataAnnotations.Schema doesn't work or doesn't support I think.
I am using a code-first approach and my database already exists, and also not using ADO.net Entity Data Model.
I already used the [Table] attribute and DatabaseGenerated attribute, it's not working causing a compilation error to occur.
This is my code:
Entity class:
public class myclass
{
public myclass()
{
//
// TODO: Add constructor logic here
//
}
[Key]
public int RECORDID { get; set; }
public string AA { get; set; }
public string CAT { get; set; }
public string CS { get; set; }
public int? FS { get; set; }
public int? CA { get; set; }
public int? DR { get; set; }
public int? UM { get; set; }
public int? ID { get; set; }
public double LAT { get; set; }
public double LON { get; set; }
public int? NIC { get; set; }
}
DbContext class:
public class classContext : DbContext
{
public classContext() : base("name=DBConnection")
{
//Disable initializer
Database.SetInitializer<classContext>(null);
}
public DbSet<myclass> myclasses { get; set; }
}
Or I have to add this override method of model creating, is it helpful or not?
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Entity<myclass>().ToTable("Datatbl");
}
Help me out. Thanks
You can Use Table attribute over your class:
[Table("Datatbl")]
public class myclass
{
}
I have a problem with devising a many to many relationship in code first. EF is creating the Junction table and associating the Fk's as I would expect, however when i try to access the User's MailingList collection, there are no entries.
I've implemented test data on Initialise via Seeding, the data is al present in the database.
I think the problem lies with the constructors for Users and MailingLists, but I'm uncertain. I want to be able to navigate the navigational property of User.MailingLists.
var user = db.Users.Find(1);
Console.WriteLine("{0}", user.EmailAddress); //This is Fine
Console.WriteLine("{0}", user.Address.PostCode); /This is Fine
foreach (MailingList ml in user.MailingLists) // this is 0
{
Console.WriteLine("{0}", ml.Name);
}
My model is below:-
public class User : IEntityBase
{
public User()
{
MailingLists = new List<MailingList>();
}
public int Id { get; set; }
public string Forename { get; set; }
public string Surname { get; set; }
public string EmailAddress { get; set; }
public DateTime? DateLastUpdated { get; set; }
public DateTime DateCreated { get; set; }
public bool IsDeleted { get; set; }
public virtual Address Address { get; set; }
public ICollection<MailingList> MailingLists { get; set; }
}
public class MailingList : IEntityBase
{
public MailingList()
{
Users = new List<User>();
}
public int Id { get; set; }
public string Name { get; set; }
public DateTime? DateLastUpdated { get; set; }
public DateTime DateCreated { get; set; }
public bool IsDeleted { get; set; }
public ICollection<User> Users { get; set; }
}
public class Address : IEntityBase
{
public int Id { get; set; }
public string AddressLine1 { get; set; }
public string AddressLine2 { get; set; }
public string AddressLine3 { get; set; }
public string City { get; set; }
public string County { get; set; }
public string PostCode { get; set; }
public DateTime? DateLastUpdated { get; set; }
public DateTime DateCreated { get; set; }
public bool IsDeleted { get; set; }
}
Any suggestions welcome.
You are neither eager loading the MailingList entries with the query, nor fulfulling the requirements for a lazy loading proxy so there is no way EF can populate the collection.
To allow lazy loading, change the MailingList property to be virtual to allow the EF proxy to override it.
To use eager loading, use Include() (an extension method in System.Data.Entity) in the query to specify that the MailingList should be loaded.