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);
}
}
This article might help.
You should use .Include() to load any related properties.
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>();
}
}
Related
Customer
public class Customer
{
public Customer()
{
Addresses = new List<Address>();
Reviews = new List<Review>();
Products = new List<Product>();
}
[Key]
public string Email { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
public string Password { get; set; }
public Address DefaultAddress { get; set; }
public int DefaultAddressId { get; set; }
public List<Address> Addresses { get; set; }
public List<Review> Reviews { get; set; }
public List<Product> Products { get; set; }
}
Product
public class Product
{
public Product()
{
Reviews = new List < Review >();
}
public int Id { get; set; }
public Category Category { get; set; }
public string Name { get; set; }
public string Description { get; set; }
public string Specification { get; set; }
public List<Review> Reviews { get; set; }
public List<Customer> Customers { get; set; }
}
Review
public class Review
{
public int Id { get; set; }
public string Text { get; set; }
public int Stars { get; set; }
[Required]
public int ProductId { get; set; }
[Required]
public string CustomerId { get; set; }
}
}
Generated model
I want the relationship between Review and Customer to 1 to many not 0..1 to many. Each review must belong to one customer. I don't understand how the relationship is mapped properly for Review - Product but not for the customer.
i only used Customer and Review models since those are the once you wanted an answer.
Following is the your model classes should be.
public class Customer
{
public Customer()
{
Reviews = new HashSet<Review>();
}
[Key]
public string Email { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
public string Password { get; set; }
public ICollection<Review> Reviews { get; set; }
}
public class Review
{
public int Id { get; set; }
public string Text { get; set; }
public int Stars { get; set; }
[Required]
public int ProductId { get; set; }
[Required]
public string CustomerId { get; set; }
[ForeignKey("CustomerId")]
public Customer Customer { get; set; }
}
this way you can have customers Review collection and cast it in to a list if you want.use Include() method in your linq query to lazy load the customers review collection.
for an example:
var customer = dbContext.Customer.Include("Reviews").where(x => x.Email == "john#gmail.com").FirstOrDefault();
My question is about how can i select some one-two column from those tables are included and at the end when i am selecting as list it is returning list of parent object but child are contain those column i mention to select?
var testq = _db.Homes
.Include(x => x.Indexs.Cities.Proviences.Regions)
.Include(x => x.Images)
.Select(x => new Homes {
Images = x.Images,
Address = x.Address,
Indexs.Cities.Proviences.Regions =
x.Indexs.Cities.Proviences.Regions.Name });
At the end I need to have list of home model (List) and just images and Address and region name have value and important just those are selected from database not all infromation in the tables. I am trying to make a query with better performance
Edit Add Models
public partial class dbContext : DbContext
{
public virtual DbSet<City> Cities { get; set; }
public virtual DbSet<Province> Provinces { get; set; }
public virtual DbSet<Region> Regions { get; set; }
public virtual DbSet<Index> Indexs { get; set; }
public virtual DbSet<Home> Homes { get; set; }
public virtual DbSet<Images> Imageses { get; set; }
}
public partial class Home
{
public Home()
{
Imageses = new HashSet<Images>();
}
[Key]
public int IDHome { get; set; }
[Required]
[StringLength(5)]
public string Cap { get; set; }
[Required]
[StringLength(10)]
public string Number { get; set; }
[Required]
[StringLength(50)]
public string Address { get; set; }
....
public virtual Index Indexs { get; set; }
public virtual ICollection<Images> Imageses { get; set; }
}
public class Index
{
public int ID { get; set; }
public int IDHome { get; set; }
....
public virtual City Cities { get; set; }
}
public partial class City
{
[Key]
public int ID { get; set; }
public int IDProvincia { get; set; }
public decimal Latitudine { get; set; }
public decimal Longitudine { get; set; }
[Required]
[StringLength(100)]
public string Name { get; set; }
....
public virtual Province Provinces { get; set; }
}
public partial class Province
{
[Key]
public int ID { get; set; }
public int IDRegione { get; set; }
[Required]
[StringLength(50)]
public string Name { get; set; }
[Required]
[StringLength(3)]
public string Init { get; set; }
...
public virtual Region Regions { get; set; }
}
public partial class Region
{
[Key]
public int ID { get; set; }
[Required]
[StringLength(50)]
public string Name { get; set; }
public DateTime DataInsert { get; set; }
...
}
public class Images
{
public int ID { get; set; }
public string Path { get; set; }
...
}
absolutely tables have more column just add here as example
you have to define a new type with the fields you need, or use an anonymous type.
.Select(x => new {
Images = x.Images,
Address = x.Address,
Indexs.Cities.Proviences.Regions =
x.Indexs.Cities.Proviences.Regions.Name });
Hi guys I am spinning wheels on this one. I am using EF6 and ASP.Net 4.6. I have a given table which has student information and parent information. A student can have many parents and a parent can have many students. Call this table 'Contact'. I am to create a table called 'Request' which will hold information for a parent submitting a request for his student. I will create a lookup table with two columns, one for student id and one for parent id called 'StudentParents'. I want to be able to have the parent log in, select his student from a drop down of all of his students and submit the request. The many to many relationship is throwing me off as far as my include statements. How can I get EF to set up this structure so that when I GetRequest(id) I can get the Student info and the Parent info to be included? Here is my code that wont Include anything other than the request.
public class Contact
{
[Key]
public int id { get; set; }
public string student_id { get; set; }//This is the Student ID
public string last_name { get; set; }
public string first_name { get; set; }
public string middle_initial { get; set; }
public string grade { get; set; }
public int current_school_id { get; set; }
public string current_school_name { get; set; }
[Display(Name = "Parent Last Name")]
public string contact_first_name { get; set; }
[Display(Name = "Parent Middle Name")]
public string contact_middle_name { get; set; }
[Display(Name = "Parent Last Name")]
public string contact_last_name { get; set; }
public string contact_relationship { get; set; }
[Display(Name = "Parent Email")]
public string contact_email { get; set; }
[Display(Name = "Parent Address")]
public string login { get; set; }//This is the Parent ID
public string Classif_description { get; set; }
}
public class Request
{
[Key]
public int id { get; set; }
public Student student_id { get; set; }
public Contact login { get; set; }
[Display(Name = "First School Choice")]
public string firstSchool { get; set; }
[Display(Name = "Second School Choice")]
public string secSchool { get; set; }
[Display(Name = "Rising Grade")]
public string rising_grade { get; set; }
public DateTime ReqSubmitted { get; set; }
public string ReqStatus { get; set; }
public DateTime Created { get; set; }
public DateTime Modified { get; set; }
public string ModifBy { get; set; }
}
public class Parent
{
public int id { get; set; }
public string contact_first_name { get; set; }
public string contact_middle_name { get; set; }
public string contact_last_name { get; set; }
public string contact_relationship { get; set; }
public string contact_email { get; set; }
public string contact_address { get; set; }
public string contact_city { get; set; }
public string contact_zip { get; set; }
[Key]
public string login { get; set; }
public string contact_pw { get; set; }
public string phone { get; set; }
public string phone_type { get; set; }
public Parent() { }
public virtual ICollection<Student> Students { get; set; }
}
public class Student
{
[Key]
public int id { get; set; }
public int student_id { get; set; }
public string last_name { get; set; }
public string first_name { get; set; }
public string middle_initial { get; set; }
public DateTime birthdate { get; set; }
public string gender { get; set; }
public string grade { get; set; }
public string Fed_race_description { get; set; }
public string Classif_description { get; set; }
public int current_school_id { get; set; }
public string current_school_name { get; set; }
public int home_school_id { get; set; }
public string home_school_name { get; set; }
public Student()
{
this.Parents = new HashSet<Parent>();
}
public virtual ICollection<Parent> Parents { get; set; }
}
public class OEContext : DbContext
{
public OEContext() : base("name=OEContext")
{
}
public DbSet<Request> Requests { get; set; }
public DbSet<Parent> Parents { get; set; }
public DbSet<Contact> Contacts { get; set; }
public DbSet<Student> Students { get; set; }
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Entity<Parent>()
.HasMany(s => s.Students)
.WithMany()
.Map(x =>
{
x.MapLeftKey("login");
x.MapRightKey("student_id");
x.ToTable("StudentParents");
}
);
base.OnModelCreating(modelBuilder);
}
}
Changed the strategy. Made Request have many Contacts. So I added a constructor to the request:
public Request()
{
Contacts = new List<Contact>();
}
public virtual ICollection<Contact> Contacts { get; set; }
Next I changed the contact class:
public int ContactId { get; set; }
public Contact() { }
public virtual Request Request { get; set; }
With this relationship I can pull both Parents and a student from the Contacts associated with the Request.
I want to have a one to many relationship in between instructor and course. How can I achieve it? Below is what I have as of now.
public class Instructor
{
//[Key]
public int id { get; set; }
public string name { get; set; }
public string address { get; set; }
public string email { get; set; }
}
public class Course
{
//[Key]
public int id { get; set; }
[DisplayName("Course")]
[Required(ErrorMessage = "CSExxx")]
public string progId { get; set; }
public string name { get; set; }
public string semester { get; set; }
public string description { get; set; }
public virtual Instructor instructor { get; set; }
}
You need to add a virtual collection of Course to Instructor
public class Instructor
{
//[Key]
public int id { get; set; }
public string name { get; set; }
public string address { get; set; }
public string email { get; set; }
public virtual ICollection<Course> Courses { get; set; }
}
public class Course
{
//[Key]
public int id { get; set; }
[DisplayName("Course")]
[Required(ErrorMessage = "CSExxx")]
public string progId { get; set; }
public string name { get; set; }
public string semester { get; set; }
public string description { get; set; }
public virtual Instructor instructor { get; set; }
}
In OnModelCreating in your DataContext
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Entity<Instructor>().HasMany(i => i.Courses).WithRequired(c => c.Instructor).HasForeignKey(c => c.instructor).WillCascadeOnDelete(true);
}
I have few Domain Models - Address, Customer, Employee, StoreLocation. Address has many to one relationship with Customerand Employee and one to one relationship with StoreLocation.
public class Address
{
public int Id;
public string Line1 { get; set; }
public string Line2 { get; set; }
public string Line3 { get; set; }
}
public class Customer
{
public int Id { get; set; }
public string Name { get; set; }
public IList<Address> Addresses { get; set; }
}
public class StoreLocation
{
public int Id { get; set; }
public string ShortCode { get; set; }
public string Description { get; set; }
public Address Address { get; set; }
}
public class Employee
{
public int Id { get; set; }
public string Name { get; set; }
public DateTime Dob { get; set; }
public IList<Address> Addresses { get; set; }
}
How to Map this relationship?. I am using ASP.NET MVC 3.0 and Entity Framework 4.1.
If you are using code-first (I think you want this, else, you have to edit your Q), the first way is the way explained below:
Entities:
public class Address {
[Key]
public int Id { get; set; }
public string Line1 { get; set; }
public string Line2 { get; set; }
public string Line3 { get; set; }
public virtual Customer Customer { get; set; }
public virtual StoreLocation StoreLocation { get; set; }
public virtual Employee Employee { get; set; }
public int? CustomerId { get; set; }
public int? EmployeeId { get; set; }
}
public class Customer {
[Key]
public int Id { get; set; }
public string Name { get; set; }
public virtual ICollection<Address> Addresses { get; set; }
}
public class StoreLocation {
[Key]
public int Id { get; set; }
public string ShortCode { get; set; }
public string Description { get; set; }
public virtual Address Address { get; set; }
}
public class Employee {
[Key]
public int Id { get; set; }
public string Name { get; set; }
public DateTime Dob { get; set; }
public virtual ICollection<Address> Addresses { get; set; }
}
DbContext inherited class:
public class ManyOneToManyContext : DbContext {
static ManyOneToManyContext() {
Database.SetInitializer<ManyOneToManyContext>(new ManyOneToManyInitializer());
}
public DbSet<Address> Addresses { get; set; }
public DbSet<Customer> Customers { get; set; }
public DbSet<StoreLocation> StoreLocations { get; set; }
public DbSet<Employee> Employees { get; set; }
protected override void OnModelCreating(DbModelBuilder modelBuilder) {
modelBuilder.Conventions.Remove<IncludeMetadataConvention>();
modelBuilder.Entity<Customer>().HasMany(c => c.Addresses).WithOptional(a => a.Customer).HasForeignKey(a => a.CustomerId);
modelBuilder.Entity<StoreLocation>().HasRequired(s => s.Address).WithOptional(a => a.StoreLocation).Map(t => t.MapKey("AddressId"));
modelBuilder.Entity<Employee>().HasMany(e => e.Addresses).WithOptional(a => a.Employee).HasForeignKey(e => e.EmployeeId);
}
}
Context Initializer:
public class ManyOneToManyInitializer : DropCreateDatabaseAlways<ManyOneToManyContext> {
protected override void Seed(ManyOneToManyContext context) {
}
}
That will create the db-schema below:
Let me know if you have any questions or need clarifications on any part.