Entity Framework 6

CreateDatabaseIfNotExists: boshlang‘ich holda ishlatiladigan initsializator. U DBdagi ma’lumotlarni avtomatik o‘chirmaydi. Agar model va ma’lumotlar kontekstini tuzilmasi o‘zgartirilgan vaqtda xatolikni qaytaradi.

DropCreateDatabaseWhenModelChanges: ushbu initsializator model va DB jadvallari mosligini aniqlaydi. Agar modelda jadvalga moslik mavjud bo‘lmasa, DB qayta yaratiladi.

DropCreateDatabaseAlways: Ushbu initsializator orqali DBst qayta shakllantiriladi.

Ushbu initsializatorlarning biridan foydalanish lozim. Buning uchun bizga Seed metodi xizmat qiladi:

1. 
   Phones.cs
   

using System.Data.Entity;

namespace Init

{
class Phone
{
public int Id { get; set; }
public string Name { get; set; }
public int Price { get; set; }
}
}

2. 
   MobileContext.cs
   

using System.Data.Entity;

namespace Init

{
class MobileContext : DbContext
{
static MobileContext()
{
Database.SetInitializer(new MyContextInitializer());
}

public MobileContext()

: base("DefaultConnection")
{ }
public DbSet Phones { get; set; }
}
}

3. 
   MyContextInitializer.cs
   

using System.Data.Entity;

namespace Init

{
class MyContextInitializer : DropCreateDatabaseAlways
{
protected override void Seed(MobileContext db)
{
Phone p1 = new Phone { Name = "Samsung Galaxy S5", Price = 14000 };
Phone p2 = new Phone { Name = "Nokia Lumia 630", Price = 8000 };

db.Phones.Add(p1);

db.Phones.Add(p2);
db.SaveChanges();
}
}

}

4.