Below is a POCO class i set up with Entity Framework Code first. How can i Query my database so that I can return all brands of a specific category?
Example: You have a list of categories and you click on one. It shows all brands of products available under that category.
I don't know if my classes are set up correctly to do this.
public class Product
{
[Key,ScaffoldColumn(false)]
public int ProductID { get; set; }
public string ProductName { get; set; }
public int? CategoryID { get; set; }
public virtual Category Category { get; set; }
public int? BrandID { get; set; }
public virtual Brand Brand { get; set; }
}
public class Brand
{
[ScaffoldColumn(false)]
public int BrandID { get; set; }
public string BrandName { get; set; }
}
public class Category
{
[ScaffoldColumn(false)]
public int CategoryID { get; set; }
public string CategoryName { get; set; }
public virtual ICollection<Product> Products { get; set; }
}
What about
context.Products.
Where(p => p.Category.CategoryID == categoryToFind).Select(p => p.Brand);
or
var brands = context.Products.
Where(p => p.Category.CategoryID == categoryToFind).
Select(p => p.Brand.BrandName).Distinct().ToList();
if you just need brand names.
Related
I'm creating a KPI dashboard that displays the total income from orders. The business logic is that each item is linked to a type of event with a many to many relationship , and linked to a supplier type via a one to many relationship. And there are different suppliers which sell these items based on the supplier type. There is also a table that links suppliers to their order by using the orderItemId and supplierId. What I'm trying to achieve is the following:
Get all orders that have been successfully fulfilled and get their order items.
Get the supplier order items from the table I mentioned above using the order items.
Once I have the supplier order items, I want to group them by the supplierId, and iem event type id so that I can display the items that each supplier sold of each event type.
Supplier
Event Type
List of items
Supplier
Event Type
List of items
The above is what I want to happen. I managed to group them by supplier id but I'm struggling to group them by eventTypeId because of the many to many relationship between the item and the event types.
Here are the models:
public partial class Item
{
public Item()
{
Favorites = new HashSet<Favorite>();
ItemDetails = new HashSet<ItemDetail>();
ItemEventTypes = new HashSet<ItemEventType>();
OrderItems = new HashSet<OrderItem>();
SupplierItems = new HashSet<SupplierItem>();
}
[Key]
public int Id { get; set; }
[StringLength(250)]
public string Image { get; set; }
public string Description { get; set; }
[StringLength(200)]
public string Title { get; set; }
public int? CategoryId { get; set; }
[Column("isDeleted")]
public bool? IsDeleted { get; set; }
public double? Price { get; set; }
public int? EventTypeId { get; set; }
public int? NumberOfGuestsId { get; set; }
public double? DaberniPrice { get; set; }
public double? RegularPrice { get; set; }
public int? Tax { get; set; }
[Column("SupplierTypeID")]
public int? SupplierTypeId { get; set; }
[Column("SortID")]
public int? SortId { get; set; }
public bool? IsDisabled { get; set; }
public int? Min { get; set; }
public int? Max { get; set; }
public int? Increment { get; set; }
public bool? IsShisha { get; set; }
public bool? IsSoldByPackage { get; set; }
[Column("ImageAR")]
[StringLength(250)]
public string ImageAr { get; set; }
[Column("DescriptionAR")]
public string DescriptionAr { get; set; }
[Column("TitleAR")]
[StringLength(250)]
public string TitleAr { get; set; }
public int? Capacity { get; set; }
[ForeignKey(nameof(CategoryId))]
[InverseProperty(nameof(Catrgory.Items))]
public virtual Catrgory Category { get; set; }
[ForeignKey(nameof(NumberOfGuestsId))]
[InverseProperty(nameof(NumberOfGuest.Items))]
public virtual NumberOfGuest NumberOfGuests { get; set; }
[ForeignKey(nameof(SupplierTypeId))]
[InverseProperty("Items")]
public virtual SupplierType SupplierType { get; set; }
[InverseProperty(nameof(Favorite.Item))]
public virtual ICollection<Favorite> Favorites { get; set; }
[InverseProperty(nameof(ItemDetail.Item))]
public virtual ICollection<ItemDetail> ItemDetails { get; set; }
[InverseProperty(nameof(ItemEventType.Item))]
public virtual ICollection<ItemEventType> ItemEventTypes { get; set; }
[InverseProperty(nameof(OrderItem.Item))]
public virtual ICollection<OrderItem> OrderItems { get; set; }
[InverseProperty(nameof(SupplierItem.Item))]
public virtual ICollection<SupplierItem> SupplierItems { get; set; }
}
public partial class ItemEventType
{
[Key]
public int Id { get; set; }
public int? EventTypeId { get; set; }
public int? ItemId { get; set; }
public bool? IsDeleted { get; set; }
[ForeignKey(nameof(EventTypeId))]
[InverseProperty("ItemEventTypes")]
public virtual EventType EventType { get; set; }
[ForeignKey(nameof(ItemId))]
[InverseProperty("ItemEventTypes")]
public virtual Item Item { get; set; }
}
public partial class SupplierAssignedOrderItem
{
[Key]
public int Id { get; set; }
[Column("SupplierID")]
public int? SupplierId { get; set; }
[Column("ItemID")]
public int? ItemId { get; set; }
public int? Status { get; set; }
[Column(TypeName = "datetime")]
public DateTime? CreatedDate { get; set; }
[ForeignKey(nameof(ItemId))]
[InverseProperty(nameof(OrderItem.SupplierAssignedOrderItems))]
public virtual OrderItem Item { get; set; }
[ForeignKey(nameof(Status))]
[InverseProperty(nameof(OrderStatus.SupplierAssignedOrderItems))]
public virtual OrderStatus StatusNavigation { get; set; }
[ForeignKey(nameof(SupplierId))]
[InverseProperty("SupplierAssignedOrderItems")]
public virtual Supplier Supplier { get; set; }
}
Any Help is appreciated. Thanks.
I tried with EF Core,you could get orders and Supplier as follow :
DBcontext:
public class EFCoreDbContext : DbContext
{
public EFCoreDbContext(DbContextOptions<EFCoreDbContext> options)
: base(options)
{
}
public DbSet<Item> Item { get; set; }
public DbSet<Order> Order { get; set; }
public DbSet<Supplier> Supplier { get; set; }
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
modelBuilder.Entity<Item>().ToTable("Item");
modelBuilder.Entity<Order>().ToTable("Order");
modelBuilder.Entity<OrderItem>().HasKey(x => new { x.ItemId, x.OrderId });
modelBuilder.Entity<OrderItem>().HasOne(x => x.Item).WithMany(x => x.OrderItems).HasForeignKey(x => x.ItemId);
modelBuilder.Entity<OrderItem>().HasOne(x => x.Order).WithMany(x => x.OrderItems).HasForeignKey(x => x.OrderId);
modelBuilder.Entity<OrderItem>().ToTable("OrderItem");
modelBuilder.Entity<Supplier>().HasMany(x => x.Orders).WithOne(x => x.Supplier).HasForeignKey(x => x.SupplierId);
modelBuilder.Entity<Supplier>().ToTable("Supplier");
modelBuilder.Entity<SupplierItem>().HasKey(x => new { x.ItemId, x.SupplierId });
modelBuilder.Entity<SupplierItem>().HasOne(x => x.Item).WithMany(x => x.SupplierItems).HasForeignKey(x => x.ItemId);
modelBuilder.Entity<SupplierItem>().HasOne(x => x.Supplier).WithMany(x => x.SupplierItems).HasForeignKey(x => x.SupplierId);
modelBuilder.Entity<SupplierItem>().ToTable("SupplierItem");
}
controller:
var orderlist = _context.Order.Include(p => p.OrderItems).ThenInclude(q => q.Item).ToList();
var supplierlist = _context.Supplier.Include(p => p.SupplierItems).ThenInclude(q => q.Item).ToList();
And I think it'll be better if you remove some properties from your itemclass and add them to SupplierItem class,such as the price property and Event Type property.
an item may have different prices if you buy from different supplies,also in different days. If the event type is used to describe the state of the trade ,it should be removed as well.
public class Item
{
public Item()
{
OrderItems = new List<OrderItem>();
SupplierItems = new List<SupplierItem>();
}
public int ItemId { get; set; }
public string ItemName { get; set; }
public List<OrderItem> OrderItems { get; set; }
public List<SupplierItem> SupplierItems { get; set; }
}
public class Supplier
{
public Supplier()
{
Orders = new List<Order>();
SupplierItems = new List<SupplierItem>();
}
public int SupplierId { get; set; }
public string SupplierName { get; set; }
public List<Order> Orders { get; set; }
public List<SupplierItem> SupplierItems { get; set; }
}
public class SupplierItem
{
public Item Item { get; set; }
public int ItemId { get; set; }
public Supplier Supplier { get; set; }
public int SupplierId { get; set; }
public double SupplierItemPrice { get; set; }
}
If you really want to group the supplier list by two properties
you could try:
var somesupplierslist = supplierlist.GroupBy(x => new { x.SupplierId, x.SupplierName }).ToList();
I'm setting up a new e-commerce project. I want every category has many sub category and these sub categories has many products in it. My product , category and sub category classes are here;
public class Category
{
public int Id { get; set; }
public string Name { get; set; }
public List<SubCategory> SubCategories { get; set; }
}
public class SubCategory
{
public int Id { get; set; }
public string Name { get; set; }
public int ItemsInCategory { get { return Products.Count; } }
public List<Product> Products { get; set; }
public int CategoryId { get; set; }
public Category Category { get; set; }
}
public class Product
{
public Product()
{
Attributes = new List<Attribute>();
Reviews = new List<Review>();
}
public int ProductId { get; set; }
public string ProductName { get; set; }
public string BrandName { get; set; }
public decimal Price { get; set; }
public bool OnSale { get; set; }
public int SalePercantage { get; set; }
public decimal SalePrice { get; set; }
public string ShortDescription { get; set; }
public string Description { get; set; }
public int SubCategoryId { get; set; }
public SubCategory SubCategory { get; set; }
public List<Attribute> Attributes { get; set; }
public List<Review> Reviews { get; set; }
}
While I'm trying to update database I'm getting this error :
Introducing FOREIGN KEY constraint 'FK_Products_SubCategory_SubCategoryId' 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.
Could not create constraint or index. See previous errors.
How can I fix this?
You need to specify in your context the one-to-many relationship , in your case a Product has one SubCategory and a SubCategory has many Product's
modelBuilder.Entity<Product>()
.HasOne(d => d.SubCategory)
.WithMany(p => p.Products)
.HasForeignKey(d => d.SubCategoryId);
Currently I'm working with WebApi and Entity Framework, So I have 3 entities: Products, Categories and ProductCategory; their relationships are:
My problem is that Category entity has a Category Parent property, so it's recursive, my Category Controller looks like this:
public async Task<IHttpActionResult> GetCategory()
{
var category = await db.Category.Select(x=>new {
x.categoryDesc,
x.CategoryId,
x.categoryImage,
x.categoryName,
x.categoryParent
}).ToListAsync();
return Ok(category);
}
I'm returning an anonymous object, the propierty categoryParent its the same object as category so its recursive; when I fill the database with mock data in the Category table and call the get method, everything runs OK because I dont have any data en ProductCategory, but when I fill it(the ProductCategory table) the program crashes.
MY entity classes are:
public class Category {
public int CategoryId { set; get; }
public string categoryName { set; get; }
public string categoryDesc { set; get; }
public string categoryImage { set; get; }
public int? categoryParentId { set; get; }
public virtual ICollection<ProductCategory> ProductCategories { set; get; }
public virtual Category categoryParent { set; get; }
}
public class Product{
public int ProductId { set; get; }
public string productName { set; get; }
public string productDesc { set; get; }
public double productPrice { set; get; }
public string productUrl { set; get; }
public DateTime productPublishDate { set; get; }
public DateTime productModifyDate { set; get; }
public bool productStatus { set; get; }
public int productStock { set; get; }
public virtual ICollection<ProductCategory> ProductCategories { set; get; }
}
public class ProductCategory : IProductCategory {
[Required]
[Key]
[ForeignKey("Category")]
[Column(Order = 1)]
public int CategoryId { set; get; }
[Required]
[Key]
[ForeignKey("Product")]
[Column(Order = 2)]
public int ProductId { set; get; }
public virtual Product Product { set; get; }
public virtual Category Category { set; get; }
}
Can you help me to fix it?, So when I return categoryParent return it recursively, Thanks
I'm guessing you might have better luck if you explicitly state how you want the information organized, and remove the virtual property
IQueryable<Category> category = db.Category;
var result = category.Where(w => w.categoryParentId != null)
.Join(category,
child => (int)child.categoryParentId,
parent => parent.CategoryId,
(child, parent) => new {
child.categoryDesc,
child.CategoryId,
child.categoryImage,
child.categoryName,
parent
}
);
return Ok(await result.ToListAsync());
That should get you the same result as your query above, then you could remove:
public virtual Category categoryParent { set; get; }
Thank you very much but I found the solution: https://practiceaspnet.wordpress.com/2015/11/09/many-to-many-relationships-with-additional-fields/
I used fluent API to resolve the navigation recursive problem I had:
modelBuilder.Entity<Category>()
.HasMany(x => x.ProductCategories)
.WithRequired(x => x.Category)
.HasForeignKey(x=>x.CategoryId);
modelBuilder.Entity<Product>()
.HasMany(x => x.ProductCategories)
.WithRequired(x => x.Product)
.HasForeignKey(x => x.ProductId);
Basically the WithRequired method prevents a navigation property on the other side of the relationship so it stops the recursion
My question is this. Let's say I have a Category class and Product class. And they are implemented like this :
Category :
public class Category
{
public Category()
{
this.Products = new ObservableCollection<Product>();
}
public int CategoryId { get; set; }
public string Name { get; set; }
public virtual ObservableCollection<Product> Products { get; private set; }
}
And Product :
public class Product
{
public int ProductId { get; set; }
public string Name { get; set; }
public int CategoryId { get; set; }
public virtual Category Category { get; set; }
}
My question is this. If their id names were both "Id", how could I set the same relationship between Category and Product? In this example I can easily put CategoryId in product because the IDs have different names. What if they had the same name? What should I do? Thanks.
I think just renaming their Id(s) to "Id" work perfectly as you expected.
public class Category
{
public Category()
{
this.Products = new ObservableCollection<Product>();
}
public int Id { get; set; }
public string Name { get; set; }
public virtual ObservableCollection<Product> Products { get; private set; }
}
public class Product
{
public int Id { get; set; }
public string Name { get; set; }
public int CategoryId { get; set; }
public virtual Category Category { get; set; }
}
Result
I'm tring to create a DbContext with my entites on entityframework5 codefirst way. I've brands, categories and products.
But when I try to get a Product it's Brand and Category fields are null. Category is optional but Brand is not. So at least the Brand field has to be setted. I tried the code below. Is there any thing that I miss?
public DbSet<Brand> Brands { get; set; }
public DbSet<Product> Products { get; set; }
public DbSet<Category> Categories { get; set; }
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Entity<Brand>()
.HasMany(b => b.Products)
.WithRequired(p => p.Brand)
.HasForeignKey(p => p.BrandId);
modelBuilder.Entity<Category>()
.HasMany(c => c.Products)
.WithOptional(p => p.Category)
.HasForeignKey(p => p.CategoryId);
}
And on MVC controller side:
using (var db = new InonovaContext())
{
var product = db.Products.Single(p => p.Id == id);
model.Description = product.Description;
model.ImageUrl = product.ImageUrl;
model.Name = product.Name;
model.BreadCrumb = product.Brand.Name + " / " + product.Category == null ? "" : (product.Category.Name + " / ") + product.Name; // Here Brand and Category are null
}
Product class is like below
public class Product
{
public int Id { get; set; }
public int BrandId { get; set; }
public virtual Brand Brand { get; set; }
public string Name { get; set; }
public int? CategoryId { get; set; }
public virtual Category Category { get; set; }
public string ImageUrl { get; set; }
public string Description { get; set; }
}
Brand class is like below:
public class Brand
{
public int Id { get; set; }
public string Name { get; set; }
public string ThumbLogoImageUrl { get; set; }
public string Description { get; set; }
public ICollection<Product> Products { get; set; }
}
Thanks.
If you haven't declared the Brand and Category as virtual, lazyloading of the Brand and Category properties will not work.
public class Product
{
public int Id { get; set; }
public string Name { get; set; }
public virtual Brand Brand { get; set; }
public int BrandId { get; set; }
public virtual Category Category { get; set; }
public int? CategoryId { get; set; }
}
See this for more information on lazy and eager loading.