cannot map entities using entity framework core

Question

I have in database two tables: product, supplier I want the entity framework to define the supplier of each product I am getting data successfully for two tables but the supplier in the product table is null. Also, the products collection in the supplier table is null. this is my product class:

public class Product 
{       
   public int  id { get; set; }           
   [Column("Productname", TypeName = "ntext")]
   public string Name { get; set; }           
   public decimal UnitPrice { get; set; }
   public bool isDiscounted { get; set; }
   public int quantity { get; set; }            
   public int SupplierId { get; set; }
   [ForeignKey("SupplierId")]
   public  Supplier supplier { get; set; }            
}

this is the class of supplier:

public class Supplier
{           
   public int Id { get; set; }
   public string CompanyName { get; set; }
   public string ContactName { get; set; }
   public string  ContactTitle { get; set; }
   public string city { get; set; }
   public string country { get; set; }
   public string phone { get; set; }
   public string Fax { get; set; }
   public List<Product> Products { get; set; }    
 }

context class:

 public class DbConext : DbContext
 {
    public DbSet<Product> Products { get; set; }
    public DbSet<Supplier> Suppliers { get; set; }
    public DbConext(DbContextOptions<DbConext> options) : base(options)
    {
    }
    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        modelBuilder.Entity<Product>().ToTable("Product");
        modelBuilder.Entity<Supplier>().ToTable("Supplier");
        modelBuilder.Entity<Product>().HasKey("id");
        modelBuilder.Entity<Supplier>().HasKey("Id");
        modelBuilder.Entity<Product>().HasOne(p => p.supplier).WithMany(s => s.Products).HasForeignKey(p => p.SupplierId);                  
    }
 }

John Doe · Accepted Answer · 2021-08-19 09:56:02Z

2

This article might help.

You should use .Include() to load any related properties.

answered Aug 19, 2021 at 9:56

John Doe

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2 Comments

Khaled Janky Over a year ago

where to add Incclode() ? I am very new to entity framework @John Doe

John Doe Over a year ago

context.Products.Include(p => p.Supplier), where context is an instance of your DBContext class. After that you can filter your collection however you like.

SirOneOfMany · Accepted Answer · 2021-08-19 09:50:31Z

0

minimum you need is to initialize the list

public  class Supplier
{
    
   public  int Id { get; set; }
   public string CompanyName { get; set; }
   public string ContactName { get; set; }
   public string  ContactTitle { get; set; }
   public string city { get; set; }
   public string country { get; set; }
   public string phone { get; set; }
   public string Fax { get; set; }
   public  List<Product> Products { get; set; }

   public Supplier() {
      this.Products = new List<Product>();
   }
}

answered Aug 19, 2021 at 9:50

SirOneOfMany

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