实体框架中的自定义关系

Question

I have got the following three tables (just an example)

public class User
{
    public int id { get; set; }
    public string name { get; set; }
    public List<Code> Codes { get; set; }
}

public class Device
{
    public int id { get; set; }
    public string name { get; set; }
    public List<Code> Codes { get; set; }
}

public class Code
{
    public int id { get; set; }
    public int entity_id { get; set; }
    public string entity_type { get; set; }
    public string code { get; set; }
}

Now a code can either belong to a User or a Device, which will be determined by the value of entity_type (ie 'user' or 'device'). How can this be achieved in Entity Framework ?

Answer 1

You could change your Code class to

public class Code
{
    public int id { get; set; }
    public User user { get; set; }
    public Device device { get; set; }
    public string code { get; set; }
}

This way one of those properties can be null.

Hope it helps.

The drawback is that you could have a code that have a user an a device