Entity Framework Code First Database Initialization with relations

Question

I'm working on an n-Teir project and this question is focusing on the Service (Buisness logic) and Data layers. I have in the data layer, three models: Aircraft, AircraftType, and AircraftLivery. Now I have a pretty good Idea of how to initialize the database with sample data, but I'm unsure of how to relate the different types. How would I create a livery and relate it to an aircraft, or the default livery of the aircraft type? How to I relate an aircraft type to an aircraft? Below is the current code which builds but I havn't ran yet. How would I implement the last class, Sample Data? Is there anything else in this code that you see that could be done differently?

In the Data Layer:

    public abstract class ModelBase
    {
        [Key]
        public int Id { get; set; }
        public string LastUpdateUser { get; set; }
        public DateTime LastUpdateDt { get; set; }
        public bool IsDeleted { get; set; }
    }

    public class Aircraft : ModelBase
    {
        public Guid SerialNumber { get; set; }
        public string Registration { get; set; }
        public byte[] Image { get; set; }
        [ForeignKey("Id")]
        public AircraftType Type { get; set; }
        [ForeignKey("Id")]
        public AircraftLivery Livery { get; set; }
    }

    public class AircraftType : ModelBase
    {
        public string Manufacture { get; set; }
        public string ICAO { get; set; } 
        public string Name { get; set; } 

        public bool IsTailDragger { get; set; }
        public bool RetractableGear { get; set; }

        public double StallSpeedFullFlaps { get; set; }
        public double StallSpeedClean { get; set; }
        public double CruiseSpeed { get; set; }
        public double MinimumDragVelocity { get; set; }
        public int LowerThrottleLimit { get; set; }
        public int MaximumMachSpeed { get; set; }


        public int Range { get; set; }
        public int Weight { get; set; }
        public int Cruise { get; set; }
        public int MaximumPassengers { get; set; }

        [ForeignKey("Id")]
        public ICollection<AircraftLivery> Liveries { get; set; }
        [ForeignKey("Id")]
        public AircraftLivery DefaultLivery { get; set; }
    }

    public class AircraftLivery : ModelBase
    {
        public byte[] Image { get; set; }
        public string Name { get; set; }
        [ForeignKey("Id")]
        public AircraftType AircraftType { get; set; }
        [ForeignKey("ID")]
        public ICollection<AircraftLivery> Aircrafts { get; set; }
        public string Author { get; set; }
    }

    public class SampleData : DropCreateDatabaseIfModelChanges<AirlineContext>
    {
        protected override void Seed(AirlineContext context)
        {
            var aircraft = new List<Aircraft>
            {
                //new Aircraft() {},
            };

            var aircraftTypes = new List<AircraftType>
            {
                //new AircraftType() {},
            };

            var aircraftLiveries = new List<AircraftLiveries>
            {
                //new AircraftLiveries() {},
            };
        }
    }

In the Service:

    public class Global : System.Web.HttpApplication
    {
        protected void Application_Start(object sender, EventArgs e)
        {
        Database.SetInitializer(new SampleData());
        }
    }

Usman Khalid · Accepted Answer · 2013-07-07 09:11:33Z

1

Just a simple hint, I hope it will help.

public class Aircraft : ModelBase
{
        public Guid SerialNumber { get; set; }
        public string Registration { get; set; }
        public byte[] Image { get; set; }

        //This is ForeignKey to AircraftType
        public int AircraftTypeId {get;set;}

        //This is ForeignKey to AircraftLivery
        public int AircraftLiveryId {get;set;}

        //Instead of Id use AircraftTypeId
        [ForeignKey("AircraftTypeId")]
        public AircraftType Type { get; set; }
        [ForeignKey("AircraftLiveryId")]
        public AircraftLivery Livery { get; set; }
}

for collection you have to use ICollection. e.g.

public class Category
{
     [Key]
     public int Id{get;set;}

     public string Name {get;set;}

     public ICollection<SubCategory> SubCategories{get;set;}
}

public class SubCategory
{
     [Key]
     public int Id{get;set;}

     public string Name {get;set;}

     public int CategoryId {get;set;}

     [ForeignKey("CategoryId")]
     public Category Category {get;set;}
}

edited Jul 7, 2013 at 9:11

answered Jul 7, 2013 at 8:20

Usman Khalid

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5 Comments

Oxymoron Over a year ago

This is very helpful and I thank you for the insight, unfortunantly, how would I create the relations when initializing the database? Any Ideas?

Oxymoron Over a year ago

Also, with this new information, how would this work with collections?

Usman Khalid Over a year ago

Check this tutorial, It explains a lot: asp.net/mvc/tutorials/mvc-4/getting-started-with-aspnet-mvc4/…

Oxymoron Over a year ago

I'm sing several posts that have virtual when doing a relation to another model. What's that all about?

Usman Khalid Over a year ago

Read this post on Virtual Keyword : stackoverflow.com/questions/7738722/…

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