我创建了2个表示数据库实体的类.
第一实体：
public enum FlightStatus
{
checkIn,gateClosed,arrived,departedAt,unknown,canceled,expectedAt,delayed,InFlight
}
public class Flight
{
[Key]
public string FlightNumber { get; set; }
public DateTime Arrival { get; set; }
public DateTime Departure { get; set; }
public string CityOfArrival { get; set; }
public string CityOfDeparture { get; set; }
public char Terminal { get; set; }
public FlightStatus Status { get; set; }
public int Gate { get; set; }
public virtual ICollection<Passanger> PassengerList { get; set; }
public double PriceForFirstClass { get; set; }
public double PriceForBusiness { get; set; }
public double PriceForEconom { get; set; }
}
第二实体：
public enum Sex
{
M,F
}
public enum FlightClass
{
First,Business,Econom,}
public enum TicketType
{
OneWay,TwoWay,}
public class Passenger
{
[Key]
public string Passport { get; set; }
public string flightNumber { get; set; }
[ForeignKey("flightNumber")]
public virtual Flight flight { get; set; }
public string FirstName { get; set; }
public string SecondName { get; set; }
public string Nationality { get; set; }
public DateTime DateOfbirthday { get; set; }
public Sex SexOfPassanger { get; set; }
public FlightClass ClassForPassanger { get; set; }
public TicketType TypeOfTicket { get; set; }
}
然后我创建了一个DbContext：
class FlightsDatabase : DbContext
{
public DbSet<Flight> Flights { get; set; }
public DbSet<Flight> FlightsArchive { get; set; }
public DbSet<Passenger> Passengers { get; set; }
}
当我尝试使用此代码时：
using (FlightsDatabase flights = new FlightsDatabase())
{
foreach (Flight flight in flights.Flights)
{
if (Math.Abs((flight.Departure - DateTime.Now).Days) <= 1)
{
timeCame(flight,null);
}
if (flight.Departure < DateTime.Now)
{
flightsToClean.Add(flight);
}
}
moveOldFlights(flightsToClean,null);
}
我收到这个错误
Multiple object sets per type are not supported. The object sets ‘Flights’ and ‘FlightsArchive’ can both contain instances of type ‘Project_Airline_Info.Models.Flight’.
所以我的问题是如何在DbContext类中创建具有相同泛型类型的2个DBset.
解决方法
简短的回答是你不能这样做.考虑以下代码行：
var flight = context.Set<Flight>().Where(f => f.FlightNumber = "123");
它如何知道用于获取数据的集合？
可能最简单的解决方法是继承Flight类并将其用于其他DbSet：
public class ArchiveFlight : Flight
{
}
你的背景：
public class FlightsDatabase :DbContext
{
public DbSet<Flight> Flights { get; set; }
public DbSet<ArchiveFlight> FlightsArchive { get; set; }
public DbSet<Passanger> Passengers { get; set; }
}
这样做的好处是,您现在可以向归档的航班添加属性,例如归档日期：
public class ArchiveFlight : Flight
{
public DateTime DateArchived { get; set; }
}
