EF代码优先 - 无法插入NULL值插入列 [英] EF Code First - Cannot insert the value NULL into column

问题描述

所以我有这样的代码，第一类：

So I have this Code-First class:

[Table("Session")]
public partial class Session
{
    [Key]
    [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
    public int SessionID { get; set; }

    public DateTime Start { get; set; }

    public DateTime End { get; set; }

    [StringLength(255)]
    public string Type { get; set; }

    public int PatientID { get; set; }

    public virtual Patient Patient { get; set; }
}

我用的迁移，我尝试种子会话表在我的初始化

I use Migrations, and I try to seed the Sessions table in my initializer:

IList<Session> defaultSessions = new List<Session>();
defaultSessions.Add(new Session()
{
    Start = DateTime.Parse("09/01/2014 14:00:00"),
    End = DateTime.Parse("09/01/2014 14:10:00"),
    Type = "pharyngeal",
    PatientID = 1,
});
foreach (Session session in defaultSessions)
{
    context.Sessions.Add(session);
}

的

的SessionID应该是主键，自动递增，这是为什么你使用 [DatabaseGenerated（DatabaseGeneratedOption.Identity）] 右键

好还是我得到这个错误：

Well still I get this error:

无法插入NULL值插入列表列不允许
空值。 INSERT失败。该语句已终止

Cannot insert the value NULL into column table column does not allow nulls. INSERT fails. The statement has been terminated

在数据库中的表如下所示（请注意我用的LocalDB，数据库是下例如 mssqllocaldb ：结果
结果
我在做什么错

The table in the database looks like this (Note I'm using LocalDB, and the database is under the instance mssqllocaldb:

What am I doing wrong?

编辑：
我注意到，在数据库，身份是 FALSE ，看到这个截图：结果
结果
这对我奇怪，因为在最新的迁移，我做了身份的定位点（这只是我在这个问题上所提供的类），以及文件看起来是这样的：

I noted that in the database, the identity is FALSE, see this screenshot:

This strikes me weird, because in the latest migration, I did the fix on the identity (it's just the class I provided in this question), and the file looks like this:

public partial class IdentityFixes : DbMigration
{
    public override void Up()
    {
        DropPrimaryKey("dbo.Admin");
        DropPrimaryKey("dbo.Session");
        AlterColumn("dbo.Admin", "AdminID", c => c.Int(nullable: false, identity: true));
        AlterColumn("dbo.Session", "SessionID", c => c.Int(nullable: false, identity: true));
        AddPrimaryKey("dbo.Admin", "AdminID");
        AddPrimaryKey("dbo.Session", "SessionID");
    }

    public override void Down()
    {
        DropPrimaryKey("dbo.Session");
        DropPrimaryKey("dbo.Admin");
        AlterColumn("dbo.Session", "SessionID", c => c.Int(nullable: false));
        AlterColumn("dbo.Admin", "AdminID", c => c.Int(nullable: false));
        AddPrimaryKey("dbo.Session", "SessionID");
        AddPrimaryKey("dbo.Admin", "AdminID");
    }
}

正如你所看到的，标识设置为true此修复程序。我做了更新，数据库，所以我不明白为什么这不起作用。

As you can see, identity is set to true in the fix. I did Update-Database so I don't understand why this doesn't work..

推荐答案

我造成了应用迁移到现有的数据库类似的问题，所以我创建了一个空迁移，并使用SQL代码，这是我的例子：

I had a similar problem caused by applying Migrations to existing database, so I created an empty Migration and use SQL code, here is my example:

public override void Up()
{
  DropForeignKey("dbo.Bar", "FooId", "dbo.Foo");
  Sql("IF object_id(N'[dbo].[FK_Bar_Foo]', N'F') IS NOT NULL ALTER TABLE [dbo].[Bar] DROP CONSTRAINT [FK_Bar_Foo]");
  Sql("CREATE TABLE [dbo].[FooTemp] ([Id] int NOT NULL)");
  Sql("INSERT INTO [dbo].[FooTemp] ([Id]) SELECT [Id] FROM [dbo].[Foo]");
  Sql("DROP TABLE [dbo].[Foo]");
  Sql("CREATE TABLE [dbo].[Foo] ([Id] int IDENTITY (1,1) NOT NULL)");
  Sql("SET IDENTITY_INSERT [dbo].[Foo] ON");
  Sql("INSERT INTO [dbo].[Foo] ([Id]) SELECT [Id] FROM [dbo].[FooTemp]");
  Sql("SET IDENTITY_INSERT [dbo].[Foo] OFF");
  Sql("DROP TABLE [dbo].[FooTemp]");
  AddPrimaryKey("dbo.Foo", "Id");
  AddForeignKey("dbo.Bar", "FooId", "dbo.Foo", "Id");
}

public override void Down()
{
  DropForeignKey("dbo.Bar", "FooId", "dbo.Foo");
  Sql("CREATE TABLE [dbo].[FooTemp] ([Id] int NOT NULL)");
  Sql("INSERT INTO [dbo].[FooTemp] ([Id]) SELECT [Id] FROM [dbo].[Foo]");
  Sql("DROP TABLE [dbo].[Foo]");
  Sql("CREATE TABLE [dbo].[Foo] ([Id] int NOT NULL)");
  Sql("INSERT INTO [dbo].[Foo] ([Id]) SELECT [Id] FROM [dbo].[FooTemp]");
  Sql("DROP TABLE [dbo].[FooTemp]");
  AddPrimaryKey("dbo.Foo", "Id");
  AddForeignKey("dbo.Bar", "FooId", "dbo.Foo", "Id");
}

心连心

HTH

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