每个类型一张表【TPT】
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
每个继承层次一张表【TPH】
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
每个子类一张表【TPC】
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
