Linking two tables in EntityFramework CodeFirst models - entity-framework

Question

I am trying to learn asp.net MVC, by converting a web forms app I have. It's a room booking app, where there is a customer table (tblCustomerBooking) which has a one to many relationship with tblRental - so one customer can book more than one room. The fields that match each other are tblCustomerBooking.customer_id -> tblRental.customer_ref
I'm trying to use code first - and building a model class - but I can't figure out how to link the two tables, so that when I query the dbContext, it will return a customer, with one or more rentals within the same model.
My table definitions are:
CREATE TABLE [dbo].[tblCustomerBooking](
[customer_id] [bigint] IDENTITY(1,1) NOT NULL,
[room_id] [bigint] NULL,
[customer_name] [varchar](110) NULL,
[customer_email] [varchar](50) NULL
CONSTRAINT [PK_tblCustomerBooking] PRIMARY KEY CLUSTERED
(
[customer_id] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF,
ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY] TEXTIMAGE_ON [PRIMARY]
CREATE TABLE [dbo].[tblRental](
[rental_id] [bigint] IDENTITY(1,1) NOT NULL,
[room_id] [bigint] NOT NULL,
[check_in] [datetime] NOT NULL,
[check_out] [datetime] NOT NULL,
[customer_ref] [bigint] NULL,
[room_cost] [decimal](18, 2) NULL
CONSTRAINT [PK_tblRental_1] PRIMARY KEY CLUSTERED
([rental_id] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF,
ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY] TEXTIMAGE_ON [PRIMARY]
My attempt at building the model for this is:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.ComponentModel.DataAnnotations;
using System.Data.Entity.ModelConfiguration.Conventions;
using System.Data.Entity;
namespace MvcApplication23.Models
{
public class tblRental
{
[Key()]
public int rental_id { get; set; }
public int room_id { get; set; }
public DateTime check_in { get; set; }
public DateTime check_out { get; set; }
public long customer_ref { get; set; }
[ForeignKey("customer_ref")]
public tblCustomerBooking Customer {get;set;}
public decimal room_cost { get; set; }
}
public class tblCustomerBooking
{
[Key()]
public long customer_id { get; set; }
public string customer_name { get; set; }
public string customer_email { get; set; }
public ICollection<tblRental> Rentals {get;set;}
}
public class RentalContext : DbContext
{
public DbSet<tblCustomerBooking> customers { get; set; }
public DbSet<tblRental> rentals { get; set; }
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Conventions.Remove<PluralizingTableNameConvention>();
}
}
}
Controller:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Net.Http;
using System.Web.Http;
using MvcApplication23.Models;
namespace MvcApplication23.api.Controllers
{
public class RentalController : ApiController
{
private RentalContext db = new RentalContext();
// GET /api/rental/5
public IQueryable<tblCustomerBooking> Get(int id)
{
return db.customers.Include("rentals").FirstOrDefault(c=>c.customer_id==id);
}
** I've updated the info above, with the actual table names that already existed in the database **
How to I link the two tables in the model? And then given a customer_id, how would I query the DbContext to return a customer, with any related entries in the tblRental table?
Thank you very much for any pointers,
Mark

Answer 1

To link two entities, provide a navigation property:
public class Rental
{
[Key]
public int rental_id { get; set; }
public int room_id { get; set; }
public DateTime check_in { get; set; }
public DateTime check_out { get; set; }
public int customer_ref { get; set; }
[ForeignKey("customer_ref")]
public virtual Customer Customer {get;set;}
public decimal room_cost { get; set; }
}
public class Customer
{
[Key]
public int customer_id { get; set; }
public string customer_name { get; set; }
public string customer_email { get; set; }
public virtual ICollection<Rental> Rentals {get;set;}
}
And to query your customer :
return this.DataContext.customers.Include("Rentals").FirstOrDefaul(c=>c.customer_id==customerId);

Answer 2

using System.ComponentModel.DataAnnotations.Schema;
public class Rental
{
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public virtual int id { get; set; }
public virtual int room_id { get; set; }
public virtual DateTime check_in { get; set; }
public virtual DateTime check_out { get; set; }
public virtual int customer_id { get; set; }
public virtual decimal room_cost { get; set; }
#region Navigation Properties
[ForeignKey("customer_id")]
public virtual Customer Customer { get; set; }
#endregion
}
public class Customer
{
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int id { get; set; }
public string name { get; set; }
public string email { get; set; }
public virtual ICollection<Rental> Rentals {get;set;}
}