I'm quite new to EF, and I'm not really sure how to do this.
I have a many-to-many relationship, exactly like this:
When I try to add a resource (Recurso) to a profile (Perfil), I get the following error:
Invalid object name 'dbo.RecursoPerfils
Where the hell did RecursoPerfils come from?
How can I specify (preferably through attribute annotation) the table name for this relationship?
See the models below:
[Table("Perfil")]
public class Perfil
{
public Perfil()
{
this.Usuarios = new List<Usuario>();
this.Recursos = new List<Recurso>();
}
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
[Key]
public int IdPerfil { get; set; }
[Required]
public string Descricao { get; set; }
public virtual ICollection<Usuario> Usuarios { get; set; }
public virtual ICollection<Recurso> Recursos { get; set; }
}
[Table("Recurso")]
public class Recurso
{
public Recurso()
{
this.Perfis = new List<Perfil>();
}
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
[Key]
public int IdRecurso { get; set; }
[Required]
public string NomeRecurso { get; set; }
[Required]
public string Descricao { get; set; }
public virtual ICollection<Perfil> Perfis { get; set; }
}
You need to use Fluent API to configure the table name of the join table.
public class MyContext : DbContext
{
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Entity<Perfil>()
.HasMany(p => p.Recursos)
.WithMany(r => r.Perfis)
.Map(mc =>
{
mc.MapLeftKey("IdPerfil");
mc.MapRightKey("IdRecurso");
mc.ToTable("PerfilRecurso");
});
}
}
You can go through this Fluent API relationship mapping tutorial for more info
Related
I've made a dotnet ef scaffold from database and the classes generated were:
public partial class Course
{
public int Id { get; set; }
public string? Description { get; set; }
}
public partial class Student
{
public int Id { get; set; }
public string? Name { get; set; }
}
public partial class StudentCourse
{
public int? IdStudent { get; set; }
public int? IdCourse { get; set; }
public virtual Student? IdStudentNavigation { get; set; }
public virtual Course? IdCourseNavigation { get; set; }
}
I want to get a List of Student where id of Course is X
I've tried _context.Student.Include("StudentCourse").Where(x=>x.Any(....) but Intellisense does not accept "Any" function.
How can i get this ?
Any(...) is a method provided by Enumerable class so you can not use it on a single Student (which is obviously not an Enumerable object).
Your configuration of many-to-many relationship is maybe missing some lines, here is my suggestion:
public partial class Course
{
public int Id { get; set; }
public string? Description { get; set; }
public List<StudentCourse> StudentCourses { get; set; }
}
public partial class Student
{
public int Id { get; set; }
public string? Name { get; set; }
public List<StudentCourse> StudentCourses { get; set; }
}
public partial class StudentCourse
{
public int? IdStudent { get; set; }
public int? IdCourse { get; set; }
public virtual Student? StudentNavigation { get; set; }
public virtual Course? CourseNavigation { get; set; }
}
In Context file:
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
modelBuilder.Entity<StudentCourse>()
.HasOne(sc => sc.StudentNavigation)
.WithMany(s => s.StudentCourses)
.HasForeignKey(sc => sc.IdStudent);
modelBuilder.Entity<StudentCourse>()
.HasOne(sc => sc.CourseNavigation)
.WithMany(c => c.StudentCourses)
.HasForeignKey(sc => sc.IdCourse);
}
Finally, your query could be:
IEnumerable<Student> students = await _context.Students
.Include(s => s.StudentCourses)
.Where(s => s.StudentCourses.Any(sc => sc.IdCourse == X)))
I am just taking your code as example but this is not a way you design entity in EF core.
Try following though.
var students
=_context.StudentCourse.Include("IdStudentNavigation").Where(x=>x.IdCourse == 1).Select(x => x.IdStudentNavigation).ToList();
Replace one with your course id.
I like to create a DB model in ASP.Net Core 3.1. I am using Code First approach with EF Core 3.1.
I like to create a model for this relationship-
So, there is one Employee table and every employee has multiple bosses and each has multiple sub-ordinates. But every boss and every subordinate are employees also. What I have done is something like this-
Employee Model-
public class Employee
{
[HiddenInput(DisplayValue = false), Display(Name = "ID")]
[Key()]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
[Column(Order = 1)]
public Guid? Id { get; set; } = Guid.NewGuid();
[Column("Name"), Required(ErrorMessage = "Term Name should be given"), Display(Name = "Term Name", Prompt = "Please Give Term Name")]
[DataType(DataType.Text)]
public string Name { get; set; }
public ICollection<Boss> Bosses { get; set; }
public ICollection<Subordinate> Subordinates { get; set; }
............
............
}
But I am getting this error during creating the DB model by the command Add-Migration <MigrationName>-
Unable to determine the relationship represented by navigation property 'Employee.Bosses' of type 'ICollection'. Either manually configure the relationship, or ignore this property using the '[NotMapped]' attribute or by using 'EntityTypeBuilder.Ignore' in 'OnModelCreating'.
Can anyone please help?
direct many-to-many relations are not supported with ef core 3.1.
See this: https://learn.microsoft.com/de-de/ef/core/what-is-new/ef-core-5.0/whatsnew
If you cannot use ef core >= 5, than you have to create a navigation property to the EmployeeBoss entity.
Try this:
public partial class Employee
{
public Employee()
{
EmployeeBossEmployees = new HashSet<EmpoyeeBoss>();
EmployeeBossBosses = new HashSet<EmpoyeeBoss>();
}
[Key]
public int Id { get; set; }
[InverseProperty(nameof(EmpoyeeBoss.Employee))]
public virtual ICollection<EmpoyeeBoss> EmployeeBossEmployees { get; set; }
[InverseProperty(nameof(EmpoyeeBoss.Boss))]
public virtual ICollection<EmpoyeeBoss> EmployeeBossBosses { get; set; }
}
public partial class EmpoyeeBoss
{
[Key]
public int Id { get; set; }
public int BossId { get; set; }
public int EmployeeId { get; set; }
[ForeignKey(nameof(EmployeeId))]
[InverseProperty("EmployeeBossEmployees")]
public virtual Employee Employee { get; set; }
[ForeignKey(nameof(BossId))]
[InverseProperty("EmployeeBossBosses")]
public virtual Employee Boss { get; set; }
}
and include in your dbcontext:
public virtual DbSet<Employee> Employees { get; set; }
public virtual DbSet<EmpoyeeBoss> EmployeeBosses { get; set; }
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
modelBuilder.Entity<EmpoyeeBoss>(entity =>
{
entity.HasOne(d => d.Employee)
.WithMany(p => p.EmployeeBossEmployees)
.HasForeignKey(d => d.EmployeeId)
.OnDelete(DeleteBehavior.ClientSetNull);
entity.HasOne(d => d.Boss)
.WithMany(p => p.EmployeeBossBosses)
.HasForeignKey(d => d.BossId);
});
How can I make many to many relation between AspNetRoles from Identity 3.0 and my custom table? I want simple 3 table, with both PermissionId and RoleId, something like AspNetUsersRole. I have something like this:
public class Permission
{
public int PermissionId { get; set; }
public string Name { get; set; }
public virtual ICollection<ApplicationRole> Roles { get; set; }
}
public class ApplicationRole : IdentityRole
{
public virtual ICollection<Permission> Permissions { get; set; }
}
But when I want to add migration, I got error:
Unable to determine the relationship represented by navigation property 'ApplicationRole.Permissions' of type 'ICollection<Permission>'. Either manually configure the relationship, or ignore this property from the model.
EF Core (EF7) does not currently support many to many relationship without a join entity. (Reference)
So, what you should do is to create an entity class for the join table and mapping two separate one-to-many relationships. Like;
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
modelBuilder.Entity<PostTag>()
.HasKey(t => new { t.PostId, t.TagId });
modelBuilder.Entity<PostTag>()
.HasOne(pt => pt.Post)
.WithMany(p => p.PostTags)
.HasForeignKey(pt => pt.PostId);
modelBuilder.Entity<PostTag>()
.HasOne(pt => pt.Tag)
.WithMany(t => t.PostTags)
.HasForeignKey(pt => pt.TagId);
}
public class PostTag
{
public int PostId { get; set; }
public Post Post { get; set; }
public string TagId { get; set; }
public Tag Tag { get; set; }
}
Regarding to this question answer, it can be done more easily like this-
class Photo
{
public int Id { get; set; }
public ICollection<PersonPhoto> PersonPhotos{ get; set; }
}
class PersonPhoto
{
public int PhotoId { get; set; }
public Photo Photo { get; set; }
public int PersonId { get; set; }
public Person Person { get; set; }
}
class Person
{
public int Id { get; set; }
public ICollection<PersonPhoto> PersonPhotos{ get; set; }
}
Be sure to configure PersonPhoto with a composite key:
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
modelBuilder.Entity<PersonPhoto>().HasKey(x => new { x.PhotoId, x.PersonId });
}
To navigate, use a Select:
// person.Photos
var photos = person.PersonPhotos.Select(c => c.Photo);
Add This namespace-
using Microsoft.AspNetCore.Identity;
public class Permission
{
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int PermissionId { get; set; }
public string Name { get; set; }
public string UserIdFK { get; set; } //Foreign Key of Identity tbl
[ForeignKey("UserIdFK")]
public IdentityUser UserDetail { get; set; }
}
That's it, Happy coding :)
Entity Framework code first (v6) creates a columnname in the database that I don't like. In tablename SharepointMappings it adds columnname: 'SharepointDestination_DestinationId' (foreign key).
It also generates a columnname SharepointDestinationId.
I would like to have 1 column, a foreign key, with the name 'SharepointDestinationId'.
My model looks like this:
public class Destination
{
public int DestinationId { get; set; }
}
public class SharepointDestination : Destination
{
public string UserName { get; set; }
public string Password { get; set; }
public string Domain { get; set; }
public string SiteUrl { get; set; }
public string DocumentLibraryName { get; set; }
public List<SharepointMapping> Mappings { get; set; }
}
public class SharepointMapping
{
public int SharepointMappingId { get; set; }
public string SourceFieldName { get; set; }
public string DestinationFieldName { get; set; }
//[ForeignKey("SharepointDestination")]
public int SharepointDestinationId { get; set; }
//[ForeignKey("SharepointDestinationId")]
public virtual SharepointDestination SharepointDestination { get; set; }
}
//.....
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
// To use TPT inheritence
modelBuilder.Entity<SharepointDestination>().ToTable("SharepointDestinations");
//modelBuilder.Entity<SharepointMapping>()
// .HasRequired(m => m.SharepointDestination)
// .WithMany(d => d.Mappings)
// .HasForeignKey(m => m.SharepointDestinationId)
// .WillCascadeOnDelete(true);
}
It doesn't matter if i leave or add the attribute ForeignKey and it also doesn't matter if i make properties virtual or not. Completely deleting both properties on SharepointMapping or giving them a complete other name has no consequences.
I think this has something to do with the inheritence structure. Because it's 'only' a 1-n mapping.
How should I configure EF to have only 1 column with the name 'SharepointDestinationId' which should be a foreign key? (and also have the navigation property and DestinationId property on the SharepointMapping class)
Since the key of SharepointDestination is DestinationId, EF can't automatically figure it out. You could go with the annotation:
[ForeignKey("DestinationId")]
public virtual SharepointDestination SharepointDestination { get; set; }
and remove this:
[ForeignKey("SharepointDestination")]
public int SharepointDestinationId { get; set; }
The fluent should work as well if you comment out the annotation:
modelBuilder.Entity<SharepointMapping>()
.HasRequired(m => m.SharepointDestination)
.WithMany(d => d.Mappings)
.HasForeignKey(m => m.DestinationId)
.WillCascadeOnDelete(true);
The ForeignKey attribute is expecting a property name, not a table column name.
Really, you should be able to do this without any attributes.
The following should work:
public class Parent
{
public int Id { get; set; }
public string Name { get; set; }
}
public class Child
{
public int Id { get; set; }
public string Name { get; set; }
public virtual Parent Parent { get; set; }
public int ParentId { get; set; }
}
I'm trying to setup a foreign key using the following two classes.
I want to use pAcqType as an enum and store the names of the types in another table. How should I setup my classes to do this?
public class Property
{
[Key]
public int pID { get; set; }
public string pAddress { get; set; }
public string pCounty { get; set; }
public string pCity { get; set; }
public string pState { get; set; }
public string pzip { get; set; }
public virtual PropertyAcquisitionType pAcqType { get; set; } <-- foreign key
}
public class PropertyAcquisitionType
{
[Key]
public int patID { get; set; }
public string patName { get; set; }
}
UPDATE
Dan got me thinking. And I tried the following and it seems to have worked out.
It setup the foreign key on the table like I wanted. And it didn't even ask for an inverse on the other table.
public int? pAcqType { get; set; }
[ForeignKey("pAcqType")]
public PropertyAcquisitionType patID { get; set; }
Is the foreign key required (NOT NULL in the database)?
public int pAcqTypeId { get; set; }
[ForeignKey("pAcqTypeId")]
public virtual PropertyAcquisitionType pAcqType { get; set; }
Otherwise,
public int? pAcqTypeId { get; set; }
[ForeignKey("pAcqTypeId")]
public virtual PropertyAcquisitionType pAcqType { get; set; }
Then in your other class, add an inverse relationship:
public class PropertyAcquisitionType
{
[Key]
public int patID { get; set; }
public string patName { get; set; }
[InverseProperty("pAcqType")]
public virtual ICollection<Property> pOfThisType { get; set; }
}
Here is one way you could define the relationship using the fluent API (without attributes in the entity classes). Note with this method, you should not need to add a properties property on the PropertyAcquisitionType entity to satisfy the inverse side of the relationship, because the .WithMany() tells EF what it needs to know:
public class MyDbContext : DbContext
{
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Entity<Property>()
.HasKey(x => x.pID)
.HasRequired(x => x.pAcqType) // or HasOptional if using int?
.WithMany() // or WithMany(x => x.pOfThisType) if you want to add / keep the inverse property
.HasForeignKey(x => x.pAcqTypeId)
;
}
}