继承映射关系 TPH、TPT、TPC<EntityFramework6.0>

声明方式

   public class Business

    {

        [Key]

        public int BusinessId { get; protected set; }

        public string Name { get; set; }

        public string LicenseNumber { get; set; }

    }

    public class Retail : Business

    {

        public string Address { get; set; }

        public string City { get; set; }

        public string State { get; set; }

        public string ZIPCode { get; set; }

    }

    public class eCommerce : Business

    {

        public string URL { get; set; }

    }public class BusinessesContext : DbContext

    {

        public DbSet<Business> Businesses { get; set; }

        protected override void OnModelCreating(DbModelBuilder modelBuilder)

        {

            base.OnModelCreating(modelBuilder);

            modelBuilder.Entity<Business>()

                .Property(b=>b.BusinessId)

                .HasDatabaseGeneratedOption(DatabaseGeneratedOption.Identity);

            modelBuilder.Entity<Business>().ToTable("Business", "halower");

            modelBuilder.Entity<Retail>().ToTable("Retail", "halower");

            modelBuilder.Entity<eCommerce>().ToTable("eCommerce", "halower");

        }

    }

怎么使用

 private static void Main(string[] args)

        {

            using (var context = new BusinessesContext())

            {

                var retail = new Retail

                {

                    Name = "Shop and Save",

                    LicenseNumber = "200C",

                    Address = "101 Main",

                    City = "Anytown",

                    State = "TX",

                    ZIPCode = ""

                };

                context.Businesses.Add(retail);

                var web = new eCommerce

                {

                    Name = "BuyNow.com",

                    LicenseNumber = "300AB",

                    URL = "www.buynow.com"

                };

                context.Businesses.Add(web);

                context.SaveChanges();

            }

            using (var context = new BusinessesContext())

            {

                Console.WriteLine("\n--- All Businesses ---");

                foreach (var b in context.Businesses)

                {

                    Console.WriteLine("{0} (#{1})", b.Name, b.LicenseNumber);

                }

                Console.WriteLine("\n--- Retail Businesses ---");

                //OfType<T>:根据指定类型筛选

                foreach (var r in context.Businesses.OfType<Retail>())

                {

                    Console.WriteLine("{0} (#{1})", r.Name, r.LicenseNumber);

                    Console.WriteLine("{0}", r.Address);

                    Console.WriteLine("{0}, {1} {2}", r.City, r.State, r.ZIPCode);

                }

                Console.WriteLine("\n--- eCommerce Businesses ---");

                foreach (var e in context.Businesses.OfType<eCommerce>())

                {

                    Console.WriteLine("{0} (#{1})", e.Name, e.LicenseNumber);

                    Console.WriteLine("Online address is: {0}", e.URL);

                }

                Console.ReadKey();

            }

        }

生成表结构

运行效果

声明方式

  public abstract class Employee

        {

            public int EmployeeId { get; protected set; }

            public string FirstName { get; set; }

            public string LastName { get; set; }

        }

        public class FullTimeEmployee : Employee

        {

            public decimal? Salary { get; set; }

        }

        public class HourlyEmployee : Employee

        {

            public decimal? Wage { get; set; }

        }

        public class EmployeeContext: DbContext

        {

            public DbSet<Employee> Employees { get; set; }

            protected override void OnModelCreating(DbModelBuilder modelBuilder)

            {

                base.OnModelCreating(modelBuilder);

                modelBuilder.Entity<Employee>()

                    .HasKey(e => e.EmployeeId)

                    .Property(e => e.EmployeeId)

                    .HasDatabaseGeneratedOption(DatabaseGeneratedOption.Identity);

                modelBuilder.Entity<Employee>()

                    .Map<FullTimeEmployee>(m => m.Requires("EmployeeType").HasValue())

                    .Map<HourlyEmployee>(m => m.Requires("EmployeeType").HasValue());

            }

怎么使用

      private static void Main(string[] args)

        {

            using (var context = new EmployeeContext())

            {

                var fte = new FullTimeEmployee

                {

                    FirstName = "Jane",

                    LastName = "Doe",

                    Salary = 71500M

                };

                context.Employees.Add(fte);

                fte = new FullTimeEmployee

                {

                    FirstName = "John",

                    LastName = "Smith",

                    Salary = 62500M

                };

                context.Employees.Add(fte);

                var hourly = new HourlyEmployee

                {

                    FirstName = "Tom",

                    LastName = "Jones",

                    Wage = 8.75M

                };

                context.Employees.Add(hourly);

                context.SaveChanges();

            }

            using (var context = new EmployeeContext())

            {

                Console.WriteLine("--- All Employees ---");

                foreach (var emp in context.Employees)

                {

                    bool fullTime = !(emp is HourlyEmployee);

                    Console.WriteLine("{0} {1} ({2})", emp.FirstName, emp.LastName,

                        fullTime ? "Full Time" : "Hourly");

                }

                Console.WriteLine("--- Full Time ---");

                foreach (var fte in context.Employees.OfType<FullTimeEmployee>())

                {

                    Console.WriteLine("{0} {1}", fte.FirstName, fte.LastName);

                }

                Console.WriteLine("--- Hourly ---");

                foreach (var hourly in context.Employees.OfType<HourlyEmployee>())

                {

                    Console.WriteLine("{0} {1}", hourly.FirstName, hourly.LastName);

                }

            }

            Console.ReadKey();

        }

生成表结构

运行效果

声明方式

 protected override void OnModelCreating(DbModelBuilder modelBuilder)

            {

                base.OnModelCreating(modelBuilder);

                modelBuilder.Entity<Employee>()

                    .HasKey(e => e.EmployeeId)

                    .Property(e => e.EmployeeId)

                    .HasDatabaseGeneratedOption(DatabaseGeneratedOption.Identity);

                modelBuilder.Entity<FullTimeEmployee>()

                    .Map(m =>

                    {

                        m.MapInheritedProperties();

                        m.ToTable("FullTimeEmployee");

                    });

                modelBuilder.Entity<HourlyEmployee>()

                    .Map(m =>

                    {

                        m.MapInheritedProperties();

                        m.ToTable("HourlyEmployee");

                    });

            }

生成表结构