实体框架 - 继承 - 零对一关系到子对象，如何映射？ （流利的API） [英] Entity Framework - Inheritance - Zero to one Relationship to child object, how to map? (Fluent API)
问题描述
我有一个继承层次结构，其中Action是ActionCompleted和ActionCancelled的父项。 Order类具有零到一个ActionCompleted和ActionCancelled。我尝试过TPH和TPT（甚至尝试过edmx），但是无法让Entity了解Order和Child动作之间的关系，请建议如何映射？
// Classes
public class Order
{
public int OrderId {get;组; }
public string Name {get;组; }
public ActionCompleted ACO {get;组; }
public ActionCancelled ACA {get;组; }
}
public class Action
{
public int ActionID {get;组; }
public DateTime ActionDT {get;组; }
public Order Order {get;组; }
}
public class ActionCompleted：Action
{
}
public class ActionCancelled：Action
{
public int CancelledByPhysician {get;组;
}
// Mappings
$ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $
public DbSet< Order>订单{get;组; }
public DbSet< Action>行动{get;组;
protected override void OnModelCreating（DbModelBuilder modelBuilder）
{
modelBuilder.Entity< Order>（）。ToTable（Orders）;
modelBuilder.Entity< Action>（）。HasKey（a => a.ActionID）;
modelBuilder.Entity< Action>（）。Map（m => m.ToTable（Actions））
.Map< ActionCompleted>（m => m.ToTable ActionCompleted））
.Map< ActionCancelled>（m => m.ToTable（ActionCancelled））;
//modelBuilder.Entity<Action>().HasRequired(a => a.Order）.WithOptional（）。Map（m => m.MapKey（DiagOrderId））;
modelBuilder.Entity< ActionCompleted>（）。HasRequired（a => a.Order）.WithOptional（）。Map（m => m.MapKey（DiagOrderId））;
modelBuilder.Entity< ActionCancelled>（）。HasRequired（a => a.Order）.WithOptional（）。Map（m => m.MapKey（DiagOrderId））;
}
}
用于保存数据的代码：
EDISContext db = new EDISContext（）;
var ord1 = db.Orders.FirstOrDefault（o => o.OrderId == 1）;
ActionCompleted ac = new ActionCompleted（）;
ac.ActionDT = DateTime.Now;
ac.Order = ord1;
db.Actions.Add（ac）;
db.SaveChanges（）;
DB表脚本：
CREATE TABLE [dbo]。[Orders]（
[OrderId] [int] IDENTITY（1,1）NOT NULL，
[Name] [varchar]（50） NULL，
）ON [PRIMARY]
CREATE TABLE [dbo]。[Actions]（
[ActionID] [int] IDENTITY（1,1）NOT NULL，
[ActionDT] [datetime] NOT NULL，
[DiagOrderID] [int] NULL，
）ON [PRIMARY]
CREATE TABLE [dbo]。[ActionCompleted]
[ACID] [int] IDENTITY（1,1）NOT NULL，
[ActionID] [int] NOT NULL，
）ON [PRIMARY]
CREATE TABLE [dbo]。[ActionCancelled]（
[ACAID] [int] IDENTITY（1,1）NOT NULL，
[ActionID] [int] NOT NULL，
[CancelledByPhysician] [int ] NULL，
）ON [PRIMARY]
首先使用代码时，至少尝试让EF为您创建数据库总是有用的 - 这是默认行为（将查找称为SQL Server的本地实例.\SQLEXPRESS）。如果您手动创建数据库并想要控制列名称，那就是发生什么，您需要使用流畅的API指定列名。请参阅 http://msdn.microsoft.com/en -us / library / hh295845（v = vs103）.aspx 和 http://msdn.microsoft.com/en-us/library/hh295847（v = VS.103）.aspx 的一些例子应该涵盖你被卡住了on。
仅供参考，您创建的数据库将具有以下表和列名称：
CREATE TABLE [dbo]。[ActionCancelled]（
[ActionID] [int] NOT NULL，
[CancelledByPhysician] [int] NOT NULL，
PRIMARY KEY CLUSTERED（[ActionID] ASC）
）
CREATE TABLE [dbo]。[ActionCompleted]（
[ActionID] [int] NOT NULL，
PRIMARY KEY CLUSTERED（[ActionID] ASC）
）
CREATE TABLE [dbo]。[Actions]（
[ActionID] [int] IDENTITY（1,1）NOT NULL，
[ActionDT] [datetime] NOT NULL，
[Order_Orde rId] [int] NULL，
PRIMARY KEY CLUSTERED（[ActionID] ASC）
）
CREATE TABLE [dbo]。[Orders]（
[OrderId] [int] IDENTITY（1,1）NOT NULL，
[Name] [nvarchar]（max）NULL，
[ACO_ActionID] [int] NULL，
[ACA_ActionID] [int] NULL ，
PRIMARY KEY CLUSTERED（[OrderId] ASC）
）
I have a Inheritance Hierarchy where Action is parent of ActionCompleted and ActionCancelled. Order class has a zero to one ActionCompleted and ActionCancelled. I have tried TPH and TPT (even tried edmx) but unable to get Entity to understand this relationship between Order and child actions, please suggest how do I map?
//Classes
public class Order
{
public int OrderId { get; set; }
public string Name { get; set; }
public ActionCompleted ACO { get; set; }
public ActionCancelled ACA { get; set; }
}
public class Action
{
public int ActionID { get; set; }
public DateTime ActionDT { get; set; }
public Order Order { get; set; }
}
public class ActionCompleted : Action
{
}
public class ActionCancelled : Action
{
public int CancelledByPhysician { get; set; }
}
//Mappings
public class EDISContext:DbContext
{
public EDISContext()
: base("EDISContext")
{ }
public DbSet<Order> Orders { get; set; }
public DbSet<Action> Actions { get; set; }
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Entity<Order>().ToTable("Orders");
modelBuilder.Entity<Action>().HasKey(a => a.ActionID);
modelBuilder.Entity<Action>().Map(m => m.ToTable("Actions"))
.Map<ActionCompleted>(m => m.ToTable("ActionCompleted"))
.Map<ActionCancelled>(m => m.ToTable("ActionCancelled"));
//modelBuilder.Entity<Action>().HasRequired(a => a.Order).WithOptional().Map(m => m.MapKey("DiagOrderId"));
modelBuilder.Entity<ActionCompleted>().HasRequired(a => a.Order).WithOptional().Map(m => m.MapKey("DiagOrderId"));
modelBuilder.Entity<ActionCancelled>().HasRequired(a => a.Order).WithOptional().Map(m => m.MapKey("DiagOrderId"));
}
}
Code used to save data:
EDISContext db = new EDISContext();
var ord1 = db.Orders.FirstOrDefault(o => o.OrderId == 1);
ActionCompleted ac= new ActionCompleted();
ac.ActionDT = DateTime.Now;
ac.Order = ord1;
db.Actions.Add(ac);
db.SaveChanges();
Script of DB tables:
CREATE TABLE [dbo].[Orders](
[OrderId] [int] IDENTITY(1,1) NOT NULL,
[Name] [varchar](50) NULL,
) ON [PRIMARY]
CREATE TABLE [dbo].[Actions](
[ActionID] [int] IDENTITY(1,1) NOT NULL,
[ActionDT] [datetime] NOT NULL,
[DiagOrderID] [int] NULL,
) ON [PRIMARY]
CREATE TABLE [dbo].[ActionCompleted](
[ACID] [int] IDENTITY(1,1) NOT NULL,
[ActionID] [int] NOT NULL,
) ON [PRIMARY]
CREATE TABLE [dbo].[ActionCancelled](
[ACAID] [int] IDENTITY(1,1) NOT NULL,
[ActionID] [int] NOT NULL,
[CancelledByPhysician] [int] NULL,
) ON [PRIMARY]
When using code first, it's always useful to at least try letting EF create the database for you - this is the default behavior (will look for local instance of SQL Server called .\SQLEXPRESS). If you create the database manually and want to control the column names, which is what seems like is happening, you'll need to specify the column name with the fluent API. See http://msdn.microsoft.com/en-us/library/hh295845(v=vs.103).aspx and http://msdn.microsoft.com/en-us/library/hh295847(v=VS.103).aspx for some examples that should cover what you're getting stuck on.
Just for reference, the database you've created would have the following tables and column names:
CREATE TABLE [dbo].[ActionCancelled](
[ActionID] [int] NOT NULL,
[CancelledByPhysician] [int] NOT NULL,
PRIMARY KEY CLUSTERED ( [ActionID] ASC )
)
CREATE TABLE [dbo].[ActionCompleted](
[ActionID] [int] NOT NULL,
PRIMARY KEY CLUSTERED ( [ActionID] ASC )
)
CREATE TABLE [dbo].[Actions](
[ActionID] [int] IDENTITY(1,1) NOT NULL,
[ActionDT] [datetime] NOT NULL,
[Order_OrderId] [int] NULL,
PRIMARY KEY CLUSTERED ( [ActionID] ASC )
)
CREATE TABLE [dbo].[Orders](
[OrderId] [int] IDENTITY(1,1) NOT NULL,
[Name] [nvarchar](max) NULL,
[ACO_ActionID] [int] NULL,
[ACA_ActionID] [int] NULL,
PRIMARY KEY CLUSTERED ( [OrderId] ASC )
)
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