实体框架-一对一-ReferentialConstraint映射到商店生成的列 [英] Entity Framework - One-to-One - ReferentialConstraint is mapped to a store-generated column
问题描述
我应该在EF中建立简单的一对一关系。但是，当我尝试插入时收到以下错误：
I have what should be a simple one-to-one relationship to create within EF. But I'm receiving the following error when I try to insert:
ReferentialConstraint映射到商店生成的列。列：
'ACCOUNT_ID'。
ReferentialConstraint is mapped to a store-generated column. Column: 'ACCOUNT_ID'.
控制台应用程序示例：
namespace EF_ConsoleApp_Test
{
public class Program
{
public static void Main(string[] args)
{
var account = new Account
{
AccountNumber = "00123456",
CustomerValue = new Customer { FirstName = "Joe" }
};
using (var db = new MainContext())
{
db.Accounts.Add(account);
db.SaveChanges();
}
}
}
[Serializable]
[Table("CUSTOMERS")]
public class Customer
{
[Key]
[Column("CUSTOMER_ID")]
public int? Id { get; set; }
[Required]
[Column("FIRST_NAME")]
[StringLength(45)]
public string FirstName { get; set; }
public virtual Account Account { get; set; }
public Customer() { }
}
[Serializable]
[Table("ACCOUNTS")]
public class Account
{
[Key]
[DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]
[Column("ACCOUNT_ID")]
public int? Id { get; set; }
[Required]
[Column("ACCOUNT_NUMBER")]
[Display(Name = "Account Number")]
[StringLength(16)]
public string AccountNumber { get; set; }
[Column("CUSTOMER_ID")]
public int? CustomerId { get; set; }
public virtual Customer CustomerValue { get; set; }
/// <summary>
/// Default Constructor
/// </summary>
public Account() { }
}
internal class MainContext : DbContext
{
internal MainContext() : base("name=DB.Context")
{
Database.SetInitializer<MainContext>(null);
}
public virtual DbSet<Account> Accounts { get; set; }
public virtual DbSet<Customer> Customers { get; set; }
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
// Configure FK
modelBuilder.Entity<Customer>()
.HasRequired(c => c.Account)
.WithRequiredPrincipal(a => a.CustomerValue);
base.OnModelCreating(modelBuilder);
}
}
}
数据库表创建语句：
CREATE TABLE [dbo].[CUSTOMERS](
[CUSTOMER_ID] [INT] IDENTITY(1,1) NOT NULL,
[FIRST_NAME] [varchar](45) NOT NULL,
CONSTRAINT [PK_CUSTOMERS] PRIMARY KEY CLUSTERED
(
[CUSTOMER_ID] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]
GO
CREATE TABLE [dbo].[ACCOUNTS](
[ACCOUNT_ID] [INT] IDENTITY(1,1) NOT NULL,
[CUSTOMER_ID] [int] NOT NULL,
[ACCOUNT_NUMBER] [varchar](16) NOT NULL,
CONSTRAINT [PK_ACCOUNTS] PRIMARY KEY CLUSTERED
(
[ACCOUNT_ID] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]
ALTER TABLE [dbo].[ACCOUNTS] WITH CHECK ADD CONSTRAINT [FK_ACCOUNTS_CUSTOMERS] FOREIGN KEY([CUSTOMER_ID])
REFERENCES [dbo].[CUSTOMERS] ([CUSTOMER_ID])
GO
App.config：
<?xml version="1.0" encoding="utf-8"?>
<configuration>
<configSections>
<section name="entityFramework" type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" />
</configSections>
<startup>
<supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.7.1" />
</startup>
<connectionStrings>
<add name="DB.Context"
connectionString="data source=localdb;initial catalog=EF_TEST;Integrated Security=SSPI;MultipleActiveResultSets=True;App=EntityFramework;Connection Timeout=30;encrypt=true;trustServerCertificate=true;"
providerName="System.Data.SqlClient" />
</connectionStrings>
<entityFramework>
<defaultConnectionFactory type="System.Data.Entity.Infrastructure.LocalDbConnectionFactory, EntityFramework">
<parameters>
<parameter value="mssqllocaldb" />
</parameters>
</defaultConnectionFactory>
<providers>
<provider invariantName="System.Data.SqlClient" type="System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer" />
</providers>
</entityFramework>
</configuration>
要进行此项工作，我需要更改什么？
What do I need to change to make this work?
注意：
- 我正在使用EF 6.2和.NET 4.7.1。
- 我继承了该数据库架构，并且一对一关系无法更改。
- 我正试图避免只通过一次调用SaveChanges（）来明确创建交易，而不是先包装一个先创建Customer然后再创建Account的调用。
推荐答案
按惯例EF6使用所谓的
By convention EF6 represents the one-to-one relationships using the so called Shared Primary Key Association, where the PK of the dependent entity also serves as FK to the principal entity.
在您的情况下，它认为帐户.Id 成为 Customer 的FK，并且由于它是自动生成的，因此您会遇到问题。
In your case, it considers Account.Id to be the FK to Customer, and since it's auto-generated, you get the exception in question.
另一个问题是EF6不支持具有显式FK属性的一对一关系（没有 HasForeignKey fluent API类似于一个对多关系）。
The additional problem is that EF6 does not support one-to-one relationship with explicit FK property (there is no HasForeignKey fluent API similar to one-to-many relationships).
因此您需要从模型中删除 AccountId 属性，仅保留导航属性。另外，尽管不是很必要，但最好遵循命名约定，将其命名为 Account 而不是 AccountValue 。
So you need to remove the AccountId property from the model and leave only the navigation property. Also, although not strongly necessary, it would be good to follow the naming conventions and just call it Account rather than AccountValue.
换句话说，替换
[Column("CUSTOMER_ID")]
public int? CustomerId { get; set; }
public virtual Customer CustomerValue { get; set; }
与
public virtual Customer Customer { get; set; }
可以使用 MapKey 流畅的API：
The FK column name can be specified using the MapKey fluent API:
modelBuilder.Entity<Customer>()
.HasRequired(c => c.Account)
.WithRequiredPrincipal(a => a.Customer)
.Map(m => m.MapKey("CUSTOMER_ID")); // <--
您已完成。
现在，以下代码会正确地插入一个新的 Customer ，然后一个新的 Account 引用它：
Now the following correctly inserts first a new Customer and then a new Account referencing it:
var account = new Account
{
AccountNumber = "00123456",
Customer = new Customer { FirstName = "Joe" }
};
db.Accounts.Add(account);
db.SaveChanges();
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