I have two tables that need to be linked one to one by the key field email.
When I try to do this, I get an error like this:
Cannot use table 'UserSettings' for entity type 'UserSettings' since it is being used for entity type 'UserSettings' and potentially other entity types, but there is no linking relationship. Add a foreign key to 'UserSettings' on the primary key properties and pointing to the primary key on another entity type mapped to 'UserSettings'.
how I tried to implement it:
public class UserSettingsConfiguration : IEntityTypeConfiguration<UserSettings>
{
public void Configure(EntityTypeBuilder<UserSettings> builder)
{
builder.HasKey(n => n.Email);
builder.HasOne(n => n.User)
.WithOne(u => u.UserSettings)
.HasForeignKey<UserSettings>(k => k.Email)
.HasPrincipalKey<UserSettings>(k => k.Email);
}
}
UserSettings and User entities:
public class User
{
public string Email { get; set; }
public DateTime RegistrationDate { get; set; }
public string Image { get; set; }
public UserSettings UserSettings { get; set; }
}
public class UserSettings
{
public string Email { get; set; }
public int LanguageId { get; set; }
public User User { get; set; }
}
Related
I have Two Model
public class User: Entity
{
public string Gender { get; set; }
public string Name { get; set; }
}
And
public class CognitoUser : Entity
{
public string UserId { get; set; }
public User User{ get; set; }
public string CognitoName { get; set; }
}
I want to set Cognito.UserId as User.Id . I have written the following which is not working can you please correct me as i dont want to create a model CognitoUser into user model.
modelBuilder.Entity<CognitoUser>(e =>
{
e.ToTable("CognitoUser");
e.HasKey(p => p.UserId);
e.HasOne(x => x.User)
.HasForeignKey<User>(c => c.Id);
});
Primary keys are required in each Entity which is missing in your User Entity.
Using Fluent API is optional. If you set your classes right, Entity Framework will understand what you want to achieve.
Hints:
Use [Key] attribute to specify a property as primary key
Prefered primary key format would be {ClassName}{Id}
Use [DatabaseGenerated(DatabaseGeneratedOption.Identity)] to force database
to automatically generate primary key for you.
You can use Guid as primary key type, it is always unique and hassle-free
Additionally, check out the code below to see how to create a relation.
public class User: Entity
{
[Key]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public Guid UserId { get; set; }
public string Gender { get; set; }
public string Name { get; set; }
}
public class CognitoUser: Entity
{
[Key]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public Guid CognitoUserId { get; set; }
public string CognitoName { get; set; }
// relation
public Guid UserId { get; set; }
public User User { get; set; }
}
Visualization:
In entity framework core, how we can set relationship for a table, when two fields is mapping to primary key of the another table.
For example I have two table namely Users & CashBox.
Users Table
Field
Value
UserId
int
UserName
string
CashBox Table
Field
Value
CashBoxId
int
ActivatedBy
int
DeactivatedBy
int
In this case, activatedby & deactivatedby has to be linked with user table. Need to know who activated cashbox & who deactivated cashbox.
Using EF core code first approach.
With the following entity models -
public class User
{
[Key]
public int UserId { get; set; }
public string UserName { get; set; }
}
public class CashBox
{
[Key]
public int CashBoxId { get; set; }
public int ActivatedBy { get; set; }
public int DeactivatedBy { get; set; }
public User ActivatedUser { get; set; }
public User DeactivatedUser { get; set; }
}
you can configure the relationship as -
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
modelBuilder.Entity<CashBox>(e =>
{
e.HasOne(p => p.ActivatedUser)
.WithMany()
.HasForeignKey(p => p.ActivatedBy);
e.HasOne(p => p.DeactivatedUser)
.WithMany()
.HasForeignKey(p => p.DeactivatedBy);
});
}
I use identity server.
I know that if I want to add new columns, I make a new class which will inherit from IdentityUser, and in SQL Server with EF, the column will be generated. But I want to have a "Gender" column which will have a foreign key relationship with another custom-made table: "1" will be for "male", "2" for "female" etc.
I also want to make a similar relationship with another table where the programming languages of every employee will be stored.
Is that possible?
public ApplicationUser : IdentityUser
{
public string FullName {get ; set; }
public int GenderId { get ; set ;}
public ICollection<ProgrammingLanguages> PL {get ; set ;}
}
Basically you need to implement one-to-many relationship between User and Gender tables and many-to-many relationship between User and ProgrammingLanguage. Many-to-many relationship requires extra table which will contain foreign keys to User and ProgrammingLanguage tables. You then need to override OnModelCreating() method and don't forget to call the base implementation of OnModelCreating() method so that let the base implementation to setup relationships between identity tables. You can read more on how to implement relationships between entities here. Here is the sample code how this can be done:
public ApplicationUser : IdentityUser
{
public string FullName { get; set; }
public int GenderId { get; set; }
public Gender Gender { get; set; }
public ICollection<UserProgrammingLanguage> UserProgrammingLanguages { get; set;}
}
public class ProgrammingLanguage
{
public int Id { get; set; }
public string Name { get; set; }
}
public class UserProgrammingLanguage
{
public string UserId { get; set; }
public ApplicationUser User { get; set; }
public int ProgrammingLanguageId { get; set; }
public ProgrammingLanguage ProgrammingLanguage { get; set; }
}
public class Gender
{
public int Id { get; set; }
public string Name { get; set; }
}
public class ApplicationContext : IdentityDbContext<ApplicationUser>
{
public ApplicationDbContext(DbContextOptions<ApplicationDbContext> options)
: base(options)
{
}
public DbSet<Gender> Genders { get; set; }
public DbSet<ProgrammingLanguage> ProgrammingLanguages { get; set; }
protected override void OnModelCreating(ModelBuilder builder)
{
builder.Entity<UserProgrammingLanguage>(entity =>
{
entity.HasKey(pl => { pl.UserId, pl.ProgrammingLanguageId });
entity.HasOne(pl => pl.User)
.WithMany(u => u.UserProgrammingLanguages)
.HasForeignKey(pl => pl.UserId);
entity.HasOne(pl => pl.ProgrammingLanguage)
.WithMany()
.HasForeignKey(pl => pl.ProgrammingLanguageId);
}
builder.Entity<ApplicationUser>(entity =>
{
entity.HasOne(u => u.Gender)
.WithMany()
.HasForeignKey(u => u.GenderId)
.OnDelete(DeleteBehavior.Cascade);
})
base.OnModelCreating(builder);
}
}
I'm trying to make one to one relationship. I don't want to use fluent API if it is not necessary. This is what I tried so far:
[Table("UserProfile")]
public class UserProfile
{
[Key]
[DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]
public int UserId { get; set; }
public string UserName { get; set; }
}
public class Person
{
public int Id { get; set; }
[ForeignKey("UserId")]
public UserProfile UserProfile { get; set; }
}
Yes, I know there are few similar questions outhere, but none of them were short and clear. Lot of them also did not work.
It depends a little on what type of table structure you want to achieve. There are various ways of doing this, and there is a good walkthrough for all the options, from Shared Primary Key Assocations to One-to-One Foreign Key Associations in those links. Unfortunately those links make more use of Fluent than Annotations. The samples below use Annotations, as you need.
Shared Primary Key
In theory the Shared Primary Key (horizontal table partitioning, in database terms) is the "correct way". It is also the smallest change you need to do to be able to generate a migration (which will use a Shared Primary Key Association). Note that I would change Person.Id to Person.UserId to better show your intent:
// tested in EF 5 and MVC 4.5.
[Table("UserProfile")]
public class UserProfile {
[Key]
[DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]
public int UserId { get; set; }
public string UserName { get; set; }
}
[Table("Person")] // not required, added for clarity in sample code
public class Person {
// Note the change of property name to reflect that this is a shared primary key,
// using the UserId column in UserProfile as the Primary Key
[Key]
public int UserId { get; set; }
[ForeignKey("UserId")]
public virtual UserProfile UserProfile { get; set; }
}
// The generated migration:
public partial class AddTable_Person : DbMigration
{
public override void Up() {
CreateTable(
"dbo.Person",
c => new {
UserId = c.Int(nullable: false),
})
.PrimaryKey(t => t.UserId)
.ForeignKey("dbo.UserProfile", t => t.UserId)
.Index(t => t.UserId);
}
public override void Down(){
DropIndex("dbo.Person", new[] { "UserId" });
DropForeignKey("dbo.Person", "UserId", "dbo.UserProfile");
DropTable("dbo.Person");
}
}
this then gives you, in effect a 1:0-1 relationship between UserProfile (which is mandatory) and People (which is optional, but can have one per person at the most.
If you want to use Id in Person then do the following (the migration will change accordingly):
public class Person {
public int Id { get; set; }
[ForeignKey("Id")]
public UserProfile UserProfile { get; set; }
}
Shared Primary Key with two-way navigation
If you want to navigate from UserProfile to Person you have more work to do. Simply adding public virtual Person Person { get; set; } to UserProfile will give you an error:
Unable to determine the principal end of an association between the types 'Test.Models.UserProfile' and 'Test.Models.Person'. The principal end of this association must be explicitly configured using either the relationship fluent API or data annotations.
So, we fix it with [Required] on the Person.UserProfile property (Person requires UserProfile). This gives the same migration as before.
// tested in EF 5 and MVC 4.5.
[Table("UserProfile")]
public class UserProfile {
[Key]
[DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]
public int UserId { get; set; }
public string UserName { get; set; }
[ForeignKey("UserId")]
public virtual Person Person { get; set; }
}
[Table("Person")] // not required, added for clarity in sample code
public class Person {
[Key]
public int UserId { get; set; }
[ForeignKey("UserId")]
[Required]
public virtual UserProfile UserProfile { get; set; }
}
Again, this works if you use Id for Person instead of UserId:
public class Person {
[Key]
public int Id { get; set; }
[ForeignKey("Id")]
[Required]
public virtual UserProfile UserProfile { get; set; }
}
[Table("UserProfile")]
public class UserProfile
{
[Key]
[DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]
public int UserId { get; set; }
public string UserName { get; set; }
public virtual Person Person {get;set;}
}
public class Person
{
public int Id { get; set; }
public int UserProfileUserId { get; set; } //Foreign Key
public virtual UserProfile UserProfile { get; set; }
}
If you want to create a one-to-one relationship the first thing you must clarify is what is the principal and what the dependent entity in this relationship. Can a Person exist without UserProfile or can a UserProfile exist without Person?
Because you have started to apply a [ForeignKey] attribute in Person I am assuming now that Person is the dependent, i.e. it cannot exist without UserProfile.
Correct application of the [ForeignKey] attribute would then be:
public class Person
{
[ForeignKey("UserProfile")]
public int Id { get; set; }
public UserProfile UserProfile { get; set; }
}
I am not sure if that is sufficient because you don't have a Person navigation property in UserProfile. If it doesn't work add this property to UserProfile:
public Person Person { get; set; }
If you don't want to have such a navigation property you can't avoid Fluent API:
modelBuilder.Entity<Person>()
.HasRequired(p => p.UserProfile)
.WithOptional();
I got a scenario where a composite Id uniquely identifies an entity. I defined the MSSQL to have a multiple primary key on those fields. In addition I would like an auto-incremented id to be used for referencing a one-to-many relationship. Here's the schema:
public class Character
{
public virtual int Id { get; set; }
public virtual string Name { get; set; }
public virtual Region Region { get; set; }
public virtual string Realm { get; set; }
public virtual IList<CharProgression> Progression { get; set; }
}
public class CharProgression
{
public virtual int Id { get; set; }
public virtual Character Character { get; set; }
public virtual Stage Stage { get; set; }
public virtual int ProgressionPoints { get; set; }
public virtual int NumOfSaves { get; set; }
}
public class Stage
{
public virtual int Id { get; set; }
public virtual string Name { get; set; }
public virtual string Description { get; set; }
}
The mappings look like this:
class CharacterMap : ClassMap<Character>
{
public CharacterMap()
{
Table("characters");
Id(ch => ch.Id, "id").GeneratedBy.Identity().Not.Nullable();
CompositeId().KeyProperty(ch => ch.Region, "region")
.KeyProperty(ch => ch.Realm, "realm")
.KeyProperty(ch => ch.Name, "name");
HasMany<CharProgression>(ch => ch.Progression).Inverse().Cascade.All();
}
}
class CharProgressionMap : ClassMap<CharProgression>
{
public CharProgressionMap()
{
Table("char_progression");
CompositeId().KeyReference(cprog => cprog.Character, "char_id",
.KeyReference(cprog => cprog.Stage, "stage_id");
Id(cprog => cprog.Id, "id").GeneratedBy.Identity().Not.Nullable();
Map(cprog => cprog.ProgressionPoints, "progression_points");
Map(cprog => cprog.NumOfSaves, "num_of_saves");
}
}
public class StageMap : ClassMap<Stage>
{
public StageMap()
{
Table("stages");
Id(st => st.Id, "id").GeneratedBy.Identity().Not.Nullable();
Map(st => st.Name, "name");
Map(st => st.Description, "description");
}
}
Now, the thing is that I would like to use SaveOrUpdate() on a character and use the composite id for the update, since the character uniqueness is defined by those 3 fields - region, realm, name.
However, when I am referencing the Character from CharProgression, I don't want to use the composite Id as I don't want the char_progression table to hold 3 fields for identifying a character, a simple Id is enough... which is why I also defined an IDENTITY id on the Character entity.
Is what i'm trying possible? or is there another way to achieve this?
Thanks :)