I'm working with code first for a ecommerce project,
I have 2 classes: Category and Products
Relationship is one to many, Category has many products,
I want to make the foreign key as required (not null) so, if I add a product, I must enter the categoryid.
When I do so, I get this error:
Introducing FOREIGN KEY constraint 'FK_dbo.Products_dbo.Categories_categoryId' on table 'Products' may cause cycles or multiple cascade paths. Specify ON DELETE NO ACTION or ON UPDATE NO ACTION, or modify other FOREIGN KEY constraints.
Any ideas?
public class Category :IObjectWithState
{
[Key]
public int CategoryId { get; set; }
[Required]
public string Discription { get; set; }
public string Notes { get; set; }
public int ParentCategoryId { get; set; }
public virtual ICollection<Product> Products { get; set; }
public virtual ICollection<Discount> Discounts { get; set; }
public virtual ICollection<ProductList> ProductLists { get; set; }
[NotMapped]
public State state { get; set; }
}
public class Product :IObjectWithState
{
[Key]
public int ProductId { get; set; }
[Required]
public string ProductName { get; set; }
[Required]
public string ShortDiscription { get; set; }
public string LongDiscription { get; set; }
[Required]
public bool Active { get; set; }
[Required]
public int categoryId { get; set; }
[ForeignKey("categoryId")]
public Category Category { get; set; }
public ICollection<ProductImage> ProductImage { get; set; }
public ICollection<Discount> Discount { get; set; }
public ICollection<Discussion> Duscussion { get; set; }
public ICollection<ProductAttributeValue> ProductAttributeValue { get; set; }
public ICollection<ProductListItem> ProductListItem { get; set; }
public ICollection<ProductSKU> ProductSKU { get; set; }
public ICollection<RelatedProduct> RelatedProduct { get; set; }
public ICollection<Review> Review { get; set; }
public ICollection<ShoppingCart> ShoppingCart { get; set; }
}
i set cascadeDelete: to false in the Migration class
Related
I am trying to create a simple One-to-many relationship but Ef Core somehow does not recognize it. I am still a beginner in this but I think I did this by the book (defined the relationship fully) so I don't get why EF Core is throwing this error:
Unable to determine the relationship represented by navigation
'Asset.Insurance' of type 'Insurance'. Either manually configure the
relationship, or ignore this property using the '[NotMapped]'
attribute or by using 'EntityTypeBuilder.Ignore' in 'OnModelCreating'.
Those are my two models:
Asset.cs
public class Asset
{
public int AssetId { get; set; }
public string AssetName { get; set; }
[ForeignKey("AssetTypeId")]
public int AssetTypeId { get; set; }
public AssetType AssetType { get; set; }
public ICollection<AssetValue> AssetTypeValues { get; set; }
public string Brand { get; set; }
public string Model { get; set; }
public string SerialNumber { get; set; }
public string ProductNumber { get; set; }
public DateTime PurchaseDate { get; set; }
public decimal PurchasePrice { get; set; }
[ForeignKey("LocationId")]
public int? LocationId { get; set; }
public Location Location { get; set; }
[ForeignKey("InsuranceId")]
public int InsuranceId { get; set; }
public Insurance Insurance { get; set; }
[ForeignKey("OwnerId")]
public string? OwnerId { get; set; }
public AppUser Owner { get; set; }
[ForeignKey("InvoiceId")]
public int? InvoiceId { get; set; }
public Insurance Invoice { get; set; }
public string? ImagePath { get; set; }
public string? Description { get; set; }
public string CreatedBy { get; set; }
public string ModifiedBy { get; set; }
public DateTime DateCreated { get; set; }
public DateTime DateModified { get; set; }
}
Insurance.cs
public class Insurance
{
public int InsuranceId { get; set; }
[ForeignKey("InsuranceTypeId")]
public int InsuranceTypeId { get; set; }
public InsuranceType InsuranceType { get; set; }
public string Insurer { get; set; }
public DateTime StartDate { get; set; }
public DateTime EndDate { get; set; }
public string? FilePath { get; set; }
public string? Description { get; set; }
public string CreatedBy { get; set; }
public string ModifiedBy { get; set; }
public DateTime DateCreated { get; set; }
public DateTime DateModified { get; set; }
public ICollection<Asset> Assets { get; set; }
}
Also, if I remove this relationship, just for testing, migration still doesn't work and throwing errors about the other foreign keys in the Asset model. Is it because I have too many foreign keys so I have to define them in OnModelCreating?
Edit: ApplicationDbContext
public class ApplicationDbContext : IdentityDbContext<AppUser>
{
public DbSet<Asset> Assets { get; set; }
public DbSet<AssetType> AssetTypes { get; set; }
public DbSet<AssetProp> AssetProps { get; set; }
public DbSet<AssetValue> AssetValues { get; set; }
public DbSet<Location> Locations { get; set; }
public DbSet<Company> Companies { get; set; }
public DbSet<CompanyContact> CompanyContacts { get; set; }
public DbSet<Invoice> Invoices { get; set; }
public DbSet<InsuranceType> InsuranceTypes { get; set; }
public DbSet<Insurance> Insurances { get; set; }
public ApplicationDbContext(DbContextOptions<ApplicationDbContext> options)
: base(options)
{
}
}
If you specify the [ForeignKey] attribute, you need to do one of two things:
Add the attribute to the scalar property, and use the name of the navigation property; or
Add the attribute to the navigation property, and use the name of the scalar property.
So either:
[ForeignKey("Insurance")]
public int InsuranceId { get; set; }
public Insurance Insurance { get; set; }
or:
public int InsuranceId { get; set; }
[ForeignKey("InsuranceId")]
public Insurance Insurance { get; set; }
By putting the attribute on the scalar property and specifying the name of the scalar property, EF can't understand what you're trying to do.
This applies to all of your [ForeignKey("...")] attributes in the code.
NB: Since there is only one navigation property to each given entity type, and the scalar property names match the navigation property names with the Id suffix added, the [ForeignKey] attributes aren't actually required.
EDIT:
You have two navigation properties for the Insurance entity:
public Insurance Insurance { get; set; }
...
public Insurance Invoice { get; set; }
I suspect the second one should be:
public Invoice Invoice { get; set; }
I'm trying to estabilish relationship between 3 tables in c#
My models are:
Guitar:
public class Guitar
{
[Key]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
[Required]
public int Id { get; set; }
[MaxLength(30)]
[Required]
public string Model { get; set; }
public int? Price { get; set; }
[NotMapped]
public virtual Brand Brand { get; set; }
public int BrandId { get; set; }
Brand:
public class Brand
{
[Key]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
[Required]
public int Id { get; set; }
[Required]
public string Name { get; set; }
[NotMapped]
public virtual ICollection<Guitar> Guitars { get; set; }
public Brand()
{
Guitars = new HashSet<Guitar>();
}
Purchase:(Some properties might be missing here)
public class Purchase
{
[Key]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
[Required]
public int Id { get; set; }
[Required]
[MaxLength(40)]
public string BuyerName { get; set; }
[NotMapped]
public virtual Guitar Guitar { get; set; }
public int GuitarId { get; set; }
}
I've managed to link the guitar and the brand tables together, but I can't deal with the third one.
Here's my code so far:
modelBuilder.Entity<Guitar>(entity =>
{
entity.HasOne(guitar => guitar.Brand)
.WithMany(brand => brand.Guitars)
.HasForeignKey(guitar => guitar.BrandId)
.OnDelete(DeleteBehavior.ClientSetNull);
});
Foreign key in Purchases table should be the ID of the guitar, but if you have a better idea I'm open to it.
So, how do I do the same with the Purchases?
remove all [NotMapped] from your classes, And I would add a Buyer class too
public class Guitar
{
[Key]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
[Required]
public int Id { get; set; }
....
[Required]
public int? BrandId { get; set; }
public virtual Brand Brand { get; set; }
}
public class Brand
{
[Key]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
[Required]
public int Id { get; set; }
.....
public virtual ICollection<Guitar> Guitars { get; set; }
public Brand()
{
Guitars = new HashSet<Guitar>();
}
}
public class Buyer
{
[Key]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
[Required]
public int Id { get; set; }
[Required]
[MaxLength(40)]
public string Name { get; set; }
public virtual ICollection<Purchase> Purchases { get; set; }
public Bayer()
{
Purchases = new HashSet<Purchase>();
}
}
public class Purchase
{
[Key]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
[Required]
public int Id { get; set; }
[Required]
public int? BuyerId { get; set; }
public virtual Buyer Buyer { get; set; }
[Required]
public int? GuitarId { get; set; }
public virtual Guitar Guitar { get; set; }
}
and if your are using net core 5+ you don't need any fluent apis
I have two model classes Category and Recipe and their relationship in one to many. I want to Edit the Recipe and also change the category that the recipe belongs to.Thanks in advance.
public class CookContext : DbContext
{
public CookContext(): base("cookContext")
{
}
public DbSet<Recipe> Recipes { get; set; }
public DbSet<Category> Categories { get; set; }
}
public class Category
{
[Key]
public int Id { get; set; }
public string Name { get; set; }
public ICollection<Recipe> Recipes { get; set; }
}
public class Recipe
{
public int Id { get; set; }
[Required]
public string Title { get; set; }
[Required]
public string Description { get; set; }
[Required]
public string Ingridients { get; set; }
public string Image { get; set; }
public Category category { get; set; }
}
[HttpPost]
[ValidateInput(false)]
public ActionResult EditRecipe(Recipe recipe, int? categoryName)
{
var category = context.Categories.Where(c => c.Id ==
(int)categoryName).FirstOrDefault();
context.Entry(recipe).State = EntityState.Modified;
recipe.category = category;
context.SaveChanges();
}
The error messages i get are:
1.
[DbUpdateException: 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.
2.
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.
Try by adding the field CategoryId to your Recipe class, also, the category property should begin with a capital "C".
The collection property should be marked virtual if you want the data to be lazy loaded (only loaded when needed) otherwise, you may load all recipes for a given category every time you make a query:
public class Recipe
{
public int Id { get; set; }
[Required]
public string Title { get; set; }
[Required]
public string Description { get; set; }
[Required]
public string Ingridients { get; set; }
public string Image { get; set; }
public int CategoryId { get; set; }
public Category Category { get; set; }
}
public class Category
{
[Key]
public int Id { get; set; }
public string Name { get; set; }
public virtual ICollection<Recipe> Recipes { get; set; }
}
If it doesn't work try by setting up the ForeignKey attribute:
public class Recipe
{
public int Id { get; set; }
[Required]
public string Title { get; set; }
[Required]
public string Description { get; set; }
[Required]
public string Ingredients { get; set; }
public string Image { get; set; }
[ForeignKey("Category")]
public int CategoryId { get; set; }
public Category Category { get; set; }
}
public class Category
{
[Key]
public int Id { get; set; }
public string Name { get; set; }
public virtual ICollection<Recipe> Recipes { get; set; }
}
I have two tables: EstimationActivity and Activity:
public class EstimationActivity
{
public Guid Id { get; set; }
public Guid EstimateId { get; set; }
public virtual Estimate Estimate { get; set; }
public Guid ParentActivityId { get; set; }
public virtual Activity ParentActivity { get; set; }
public Guid ActivityId { get; set; }
public virtual Activity Activity { get; set; }
public double Duration { get; set; }
[Range(minimum: 0, maximum: 100)]
public int Contingency { get; set; }
public ICollection<Note> Notes { get; set; } = new List<Note>();
}
public class Activity
{
public Guid Id { get; set; }
public Guid ActivityTypeId { get; set; }
public virtual ActivityType ActivityType { get; set; }
public Guid RfcAreaId { get; set; }
public virtual RfcArea RfcArea { get; set; }
[Required]
[StringLength(maximumLength: 60, MinimumLength = 5)]
public string Name { get; set; }
}
As you can see there are two foreign keys to the Activity table(class). When I try to add a migration I get:
Introducing FOREIGN KEY constraint 'FK_EstimateActivities_Activities_ParentActivityId' on table 'EstimateActivities' may cause cycles or multiple cascade paths. Specify ON DELETE NO ACTION or ON UPDATE NO ACTION, or modify other FOREIGN KEY constraints.
I tried to restrict all cascade deletions with this, as I found in few articles:
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
foreach (var relationship in modelBuilder.Model.GetEntityTypes().SelectMany(e => e.GetForeignKeys()))
{
relationship.DeleteBehavior = DeleteBehavior.Restrict;
}
base.OnModelCreating(modelBuilder);
}
This didn't do the work. How should I go over the error?
Try use attributes [ForeignKey("SomeId")] where you set FK's and [InverseProperty("OtherClass")] overrides this convention and specifies alignment of the properties.
public class EstimationActivity
{
public Guid Id { get; set; }
public Guid EstimateId { get; set; }
public virtual Estimate Estimate { get; set; }
public Guid ParentActivityId { get; set; }
[ForeignKey("ParentActivityId")]
public virtual Activity ParentActivity { get; set; }
public Guid ActivityId { get; set; }
[ForeignKey("ActivityId")]
public virtual Activity Activity { get; set; }
public double Duration { get; set; }
[Range(minimum: 0, maximum: 100)]
public int Contingency { get; set; }
public ICollection<Note> Notes { get; set; } = new List<Note>();
}
public class Activity
{
public Guid Id { get; set; }
public Guid ActivityTypeId { get; set; }
public virtual ActivityType ActivityType { get; set; }
public Guid RfcAreaId { get; set; }
public virtual RfcArea RfcArea { get; set; }
[Required]
[StringLength(maximumLength: 60, MinimumLength = 5)]
public string Name { get; set; }
[InverseProperty("ParentActivity")]
public virtual EstimationActivity EstimationParentActivity { get; set; }
[InverseProperty("Activity")]
public virtual EstimationActivity EstimationActivity { get; set; }
}
I'm new to Entity Framework and I've run into some problems while trying to implement my ERD Code First. The situation is as follows:
ERD
A product has a group of questions (QuestionGroup). A QuestionGroup has multiple questions and can belong to multiple Questionaires. A Questionaire basically has a questiongroup and a questionorder. The questionorder is supposed to keep the position of a question within that questionaire. The Questionaire table is needed because a QuestionGroup can have multiple questionorders, and a questionorder can belong to multiple questiongroups.
Because I'm trying my best to keep this post succinct I won't post all my classes, unless you ask to see them. The Entity classes I've made look like this:
public class Question
{
[Key]
public int Id { get; set; }
[MaxLength(2000)]
[Required]
public string Text { get; set; }
public Answer Answer { get; set; }
public QuestionType Type { get; set; }
public ICollection<QuestionAnswerOption> Options { get; set; }
public ICollection<QuestionOrder> Orders { get; set; }
[ForeignKey("FollowupQuestion")]
public int QuestionId { get; set; }
public virtual Question FollowupQuestion { get; set; }
[ForeignKey("Questiongroup")]
public int QuestionGroupId { get; set; }
public virtual QuestionGroup Questiongroup { get; set; }
}
public class QuestionOrder
{
[Key]
public int Id { get; set; }
public int Position { get; set; }
[ForeignKey("Question")]
[Required]
public int QuestionId { get; set; }
public virtual Question Question { get; set; }
[ForeignKey("Questionaire")]
[Required]
public int QuestionaireId { get; set; }
public virtual Questionaire Questionaire { get; set; }
}
public class Product
{
[Key]
public int Id { get; set; }
[MaxLength(150)]
[Required]
[Index(IsUnique = true)]
public string Name { get; set; }
[MaxLength(500)]
public string Summary { get; set; }
[MaxLength(500)]
public string Examples { get; set; }
public virtual QuestionGroup QuestionGroup { get; set; }
}
public class QuestionGroup
{
[Key]
public int Id { get; set; }
public ICollection<Question> Questions { get; set; }
[ForeignKey("Product")]
public int ProductId { get; set; }
public virtual Product Product { get; set; }
}
public class Questionaire
{
[Key]
public int Id { get; set; }
public QuestionGroup Group { get; set; }
public QuestionOrder Order { get; set; }
}
The errors I'm getting look like this:
QuestionGroup_Product_Source: : Multiplicity is not valid in Role 'QuestionGroup_Product_Source' in relationship 'QuestionGroup_Product'. Because the Dependent Role properties are not the key properties, the upper bound of the multiplicity of the Dependent Role must be '*'.
QuestionOrder_Questionaire_Source: : Multiplicity is not valid in Role 'QuestionOrder_Questionaire_Source' in relationship 'QuestionOrder_Questionaire'. Because the Dependent Role properties are not the key properties, the upper bound of the multiplicity of the Dependent Role must be '*'.
QuestionType_Question_Source: : Multiplicity is not valid in Role 'QuestionType_Question_Source' in relationship 'QuestionType_Question'. Because the Dependent Role properties are not the key properties, the upper bound of the multiplicity of the Dependent Role must be '*'.
The question we've arrived at here is:
Does anyone here know of a way to fix the relations between my tables? Maybe my ERD needs some improvements too, but I think the problem is that I'm missing a few things with my Code First implementation.
what about this design for you;)
public class Customer
{
[Key, DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int CustomerId { get; set; }
public string CompanyName { get; set; }
public virtual ICollection<ContactInfo> ContactInfoes { get; set; }
public virtual ICollection<ProductQuestionaireReport> Reports { get; set; }
}
public class ContactInfo
{
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
[Key]
public int ContactInfoId { get; set; }
public string Name { get; set; }
public string Email { get; set; }
public int Telephone { get; set; }
[ForeignKey("Customer")]
public int CustomerId { get; set; }
public virtual Customer Customer { get; set; }
}
public class ProductQuestionaireReport
{
[Key, DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int ProductQuestionaireReportId { get; set; }
[ForeignKey("Product")]
public int ProductId { get; set; }
public virtual Product Product { get; set; }
public virtual QuestionaireResult Result { get; set; }
[ForeignKey("Customer")]
public int CustomerId { get; set; }
public virtual Customer Customer { get; set; }
public bool Haste { get; set; }
public string Status { get; set; }
public string Comment { get; set; }
}
public class QuestionaireResult
{
[Key, ForeignKey("ProductQuestionaireReport")]
public int ProductQuestionaireReportId { get; set; }
[ForeignKey("Questionaire")]
public int QuestionaireId { get; set; }
public virtual Questionaire Questionaire { get; set; }
public DateTime SurveyCreated { get; set; }
public Double Costs { get; set; }
public Double FunctionPoints { get; set; }
public virtual ProductQuestionaireReport ProductQuestionaireReport { get; set; }
public virtual ICollection<QuestionaireAnswer> Answers { get; set; }
}
public class Product
{
[Key, DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int ProductId { get; set; }
public string Name { get; set; }
public string Summary { get; set; }
public string Examples { get; set; }
public virtual ICollection<Questionaire> Questionaires { get; set; }
public virtual ICollection<ProductQuestionaireReport> Reports { get; set; }
}
public class QuestionaireAnswer
{
[Key, DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int QuestionaireAnswerId { get; set; }
[ForeignKey("QuestionaireResult")]
public int QuestionaireResultId { get; set; }
public virtual QuestionaireResult QuestionaireResult { get; set; }
[ForeignKey("QuestionaireQuestion")]
public int QuestionaireId { get; set; }
public virtual QuestionaireQuestion QuestionaireQuestion { get; set; }
[ForeignKey("Answer")]
public int AnswerId { get; set; }
public virtual QuestionOption Answer { get; set; }
public string Text { get; set; }
public virtual ICollection<string> Files { get; set; }
}
public class Questionaire
{
[Key, DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int QuestionaireId { get; set; }
[ForeignKey("Product")]
public int ProductId { get; set; }
public virtual Product Product { get; set; }
public virtual ICollection<QuestionaireQuestion> QuestionaireQuestions { get; set; }
public virtual ICollection<QuestionaireResult> Results { get; set; }
}
public class Question
{
[Key, DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int QuestionId { get; set; }
[ForeignKey("ParentQuestion")]
public int ParentQuestionId { get; set; }
public virtual Question ParentQuestion { get; set; }
public virtual QuestionType QuestionType { get; set; }
public virtual ICollection<QuestionOption> Options { get; set; }
}
public class QuestionType
{
[Key, ForeignKey("Question")]
public int QuestionId { get; set; }
public string Text { get; set; }
public bool IsOpenQuestion { get; set; }
public virtual Question Question { get; set; }
}
public class QuestionOption
{
[Key, DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int QuestionAnswerOptionId { get; set; }
[ForeignKey("Question")]
public int QuestionId { get; set; }
public string Text { get; set; }
public virtual Question Question { get; set; }
}
public class QuestionaireQuestion
{
[Key, DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int QuestionaireQuestionId { get; set; }
[ForeignKey("Questionaire")]
public int QuestionaireId { get; set; }
public virtual Questionaire Questionaire { get; set; }
[ForeignKey("Question")]
public int QuestionId { get; set; }
public int DisplayOrder { get; set; }
public virtual Question Question { get; set; }
}
also you must add this to OnModelCreating
modelBuilder.Entity<Customer>().HasMany(c => c.ContactInfoes)
.WithRequired(i => i.Customer).HasForeignKey(i => i.CustomerId).WillCascadeOnDelete(false);
modelBuilder.Entity<Question>().HasMany(q => q.Options)
.WithRequired(o => o.Question).HasForeignKey(o => o.QuestionId).WillCascadeOnDelete(false);
modelBuilder.Entity<QuestionaireResult>().HasMany(r => r.Answers)
.WithRequired(a => a.QuestionaireResult).HasForeignKey(o => o.QuestionaireResultId).WillCascadeOnDelete(false);
check it and feedback me ...