如何使用Fluent API在EF代码中配置TPH? [英] How to configure TPH using Fluent API in EF code-first?
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问题描述
public class Item
{
public int Id {get;组; }
public string Name {get;组; }
}
public class ItemMap:EntityTypeConfiguration< Item>
{
public ItemMap()
{
this.ToTable(items);
this.Map(m => m.Requires(type)
.HasValue(Type1)
.IsRequired());
this.HasKey(t => t.Id).Property(t => t.Id).HasColumnName(id)
.HasDatabaseGeneratedOption(DatabaseGeneratedOption.Identity);
//其他属性...
}
}
public class SecondItem:Item
{
public string其他{get;组; }
}
public class SecondItemMap:EntityTypeConfiguration< SecondItem>
{
public SecondItemMap()
{
this.Map(m => m.Requires(type)
.HasValue(Type2)
.IsRequired());
//其他属性...
}
}
当我运行应用程序时,我得到以下例外:
类型Item并且至少有一个呼叫未指定目标表名称。
如何正确映射上述模型? p>
解决方案
你应该有这样的东西:
public class BaseClassConfiguration:EntityTypeConfiguration< BaseClass> {
public BaseClassConfiguration()
:base(){
ToTable(BaseClasses,dbo);
// HasKey(tp => tp.Id);
Map< Derived1>(m => m.Requires(dis)。HasValue(C));
Map< Derived2>(m => m.Requires(dis)。HasValue(I));
Map< Derived3>(m => m.Requires(dis)。HasValue(R));
Map< Derived3>(m => m.Requires(dis)。HasValue(U));
}
}
其中
public class Derived1:BaseClass {}
等等。
==========完整代码样本==========
如你所见,甚至没有配置一个DbSet(即暴露)。
using System ;
使用System.Collections.Generic;
使用System.ComponentModel.DataAnnotations;
使用System.Data.Entity;
使用System.Data.Entity.Core.Metadata.Edm;
使用System.Data.Entity.Infrastructure;
使用System.Data.Entity.ModelConfiguration;
使用System.Data.Entity.ModelConfiguration.Conventions;
使用System.Linq;
使用System.Text;
使用System.Threading.Tasks;
命名空间testef6 {
public class Program {
public static void Main(String [] args){
String cs =Data Source = ALIASTVALK; Initial Catalog = testEF6; Integrated Security = True; MultipleActiveResultSets = True;
使用(TestContext ctx = new TestContext(cs)){
ctx.Set ()添加(新的E11 {V =a,V1 =a1})
ctx.Set&E12>()。Add(new E12 {V =b,V2 =b2});
ctx.SaveChanges();
}
使用(TestContext ctx = new TestContext(cs)){
foreach(E1 e in ctx.Set< E1>()){
控制台。 WriteLine({0,3}:{1},e.Id,eV);
}
}
}
}
public class E1 {
public Int32 Id {get;组; }
public String V {get;组; }
}
public class E11:E1 {
public String V1 {get;组; }
}
public class E12:E1 {
public String V2 {get;组; }
}
public class E1EFConfiguration:EntityTypeConfiguration< E1> {
public E1EFConfiguration()
:base(){
ToTable(tE1s,dbo);
Map< E11>(m => m.Requires(dis)。HasValue(E11));
Map< E12>(m => m.Requires(dis)。HasValue(E12));
属性(m => m.V).HasMaxLength(100);
}
}
public class E11EFConfiguration:EntityTypeConfiguration< E11& {
public E11EFConfiguration()
:base(){
属性(m => m.V1).HasMaxLength(150);
}
}
public class E12EFConfiguration:EntityTypeConfiguration< E12> {
public E12EFConfiguration()
:base(){
属性(m => m.V2).HasMaxLength(32);
}
}
public class TestContext:DbContext {
public TestContext(String cs):base(cs){
Database.SetInitializer< TestContext> (新的DropCreateDatabaseAlways< TestContext>());
}
protected override void OnModelCreating(DbModelBuilder modelBuilder){
modelBuilder.Configurations.Add(new E1EFConfiguration());
modelBuilder.Configurations.Add(new E11EFConfiguration());
modelBuilder.Configurations.Add(new E12EFConfiguration());
base.OnModelCreating(modelBuilder);
}
}
}
I have 2 models, where the second model inherits from the first one and has additional properties:
public class Item
{
public int Id { get; set; }
public string Name { get; set; }
}
public class ItemMap : EntityTypeConfiguration<Item>
{
public ItemMap()
{
this.ToTable("items");
this.Map(m => m.Requires("type")
.HasValue("Type1")
.IsRequired());
this.HasKey(t => t.Id).Property(t => t.Id).HasColumnName("id")
.HasDatabaseGeneratedOption(DatabaseGeneratedOption.Identity);
//Other properties here...
}
}
public class SecondItem : Item
{
public string Other { get; set; }
}
public class SecondItemMap : EntityTypeConfiguration<SecondItem>
{
public SecondItemMap()
{
this.Map(m => m.Requires("type")
.HasValue("Type2")
.IsRequired());
//Other properties here...
}
}
When I run the app, I get the following exception:
Map was called more than once for type 'Item' and at least one of the calls didn't specify the target table name.
How can I map the above models correctly?
解决方案
you should have something like:
public class BaseClassConfiguration : EntityTypeConfiguration<BaseClass> {
public BaseClassConfiguration()
: base() {
ToTable("BaseClasses", "dbo");
//HasKey(tp => tp.Id);
Map<Derived1>(m => m.Requires("dis").HasValue("C"));
Map<Derived2>(m => m.Requires("dis").HasValue("I"));
Map<Derived3>(m => m.Requires("dis").HasValue("R"));
Map<Derived3>(m => m.Requires("dis").HasValue("U"));
}
}
where
public class Derived1 : BaseClass {}
and so on.
========== FULL CODE SAMPLE ==========
As you can see, there is not even a DbSet configured (i.e. exposed).
using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.Data.Entity;
using System.Data.Entity.Core.Metadata.Edm;
using System.Data.Entity.Infrastructure;
using System.Data.Entity.ModelConfiguration;
using System.Data.Entity.ModelConfiguration.Conventions;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace testef6 {
public class Program {
public static void Main(String[] args) {
String cs = "Data Source=ALIASTVALK;Initial Catalog=testEF6;Integrated Security=True;MultipleActiveResultSets=True";
using (TestContext ctx = new TestContext(cs)) {
ctx.Set<E11>().Add(new E11 { V = "a", V1 ="a1"});
ctx.Set<E12>().Add(new E12 { V = "b", V2 = "b2" });
ctx.SaveChanges();
}
using (TestContext ctx = new TestContext(cs)) {
foreach (E1 e in ctx.Set<E1>()) {
Console.WriteLine("{0,3}:{1}", e.Id, e.V);
}
}
}
}
public class E1 {
public Int32 Id { get; set; }
public String V { get; set; }
}
public class E11 : E1 {
public String V1 { get; set; }
}
public class E12 : E1 {
public String V2 { get; set; }
}
public class E1EFConfiguration : EntityTypeConfiguration<E1> {
public E1EFConfiguration()
: base() {
ToTable("tE1s", "dbo");
Map<E11>(m => m.Requires("dis").HasValue("E11"));
Map<E12>(m => m.Requires("dis").HasValue("E12"));
Property(m => m.V).HasMaxLength(100);
}
}
public class E11EFConfiguration : EntityTypeConfiguration<E11> {
public E11EFConfiguration()
: base() {
Property(m => m.V1).HasMaxLength(150);
}
}
public class E12EFConfiguration : EntityTypeConfiguration<E12> {
public E12EFConfiguration()
: base() {
Property(m => m.V2).HasMaxLength(32);
}
}
public class TestContext : DbContext {
public TestContext(String cs) : base(cs) {
Database.SetInitializer<TestContext>(new DropCreateDatabaseAlways<TestContext>());
}
protected override void OnModelCreating(DbModelBuilder modelBuilder) {
modelBuilder.Configurations.Add(new E1EFConfiguration());
modelBuilder.Configurations.Add(new E11EFConfiguration());
modelBuilder.Configurations.Add(new E12EFConfiguration());
base.OnModelCreating(modelBuilder);
}
}
}
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