自数据库创建以来，支持<Database>上下文的模型已经更改

错误信息:

“自数据库创建以来，支持‘AddressBook’上下文的模型已经发生了变化。手动删除/更新数据库，或者调用database。带有IDatabaseInitializer实例的SetInitializer。例如，RecreateDatabaseIfModelChanges策略将自动删除并重新创建数据库，并可选地为其添加新数据。”

我正在尝试使用代码优先功能，以下是我写的:

var modelBuilder = new ModelBuilder();
var model = modelBuilder.CreateModel();
using (AddressBook context = new AddressBook(model))
{
    var contact = new Contact
    {
        ContactID = 10000,
        FirstName = "Brian",
        LastName = "Lara",
        ModifiedDate = DateTime.Now,
        AddDate = DateTime.Now,
        Title = "Mr."

    };
    context.contacts.Add(contact);
    int result = context.SaveChanges();
    Console.WriteLine("Result :- "+ result.ToString());
}

上下文类:

public class AddressBook : DbContext
{
    public AddressBook()
    { }
    public AddressBook(DbModel AddressBook)
        : base(AddressBook)
    {

    }
    public DbSet<Contact> contacts { get; set; }
    public DbSet<Address> Addresses { get; set; }
}

和连接字符串:

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
    <connectionStrings>
    <add name="AddressBook" providerName="System.Data.SqlClient"  
         connectionString="Data Source=MyMachine;Initial Catalog=AddressBook;
         Integrated Security=True;MultipleActiveResultSets=True;"/>
    </connectionStrings>
</configuration>

因此，数据库名称是“AddressBook”，当我试图将联系人对象添加到上下文时发生错误。我遗漏了什么吗?

当前回答

这意味着上下文上的一些更改还没有执行。请先运行Add-Migration来生成我们所做的更改(我们可能没有意识到的更改) 然后运行Update-Database

2015-08-22 08:07:48

其他回答

创建自定义上下文初始化项:

public class MyDbContextInitializer : MigrateDatabaseToLatestVersion<MyDbContext, Migrations.Configuration>
{
    public override void InitializeDatabase(MyDbContext context)
    {
        bool exists = context.Database.Exists();

        base.InitializeDatabase(context);

        if (!exists)
        {         
            MyDbSeed.Seed(context);
        }
    }       
}

注意迁移。Configuration是Package Manager Console中由迁移命令行生成的类。您可能需要将迁移的内部修饰符更改为公共修饰符。配置类。

并从您的OmModelCreating注册它:

public partial class MyDbContext : DbContext
{

    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        Database.SetInitializer<MyDbContext>(new MyDbContextInitializer());

        //other code for creating model
    }
}

2018-07-23 12:38:50

对我来说，在升级到4.3.1之后，我只是截断了EdmMetaData表，或者直接删除它。

2012-05-04 12:57:53

I am reading the Pro ASP.NET MVC 4 book as well, and ran into the same problem you were having. For me, I started having the problem after making the changes prescribed in the 'Adding Model Validation' section of the book. The way I resolved the problem is by moving my database from the localdb to the full-blown SQL Server 2012 server. (BTW, I know that I am lucky I could switch to the full-blown version, so don't hate me. ;-))) There must be something with the communication to the db that is causing the problem.

2013-01-24 20:08:57

刚刚找到答案，想在这里更新。只需要做以下事情。

public class AddressBook: DbContext
{
   protected override void OnModelCreating(ModelBuilder modelBuilder)
   {
    modelBuilder.IncludeMetadataInDatabase = false;
   }
}

2010-08-30 12:47:13

在这里，我想分享另一种防止上下文改变时模型备份错误的方法:

1)打开DbContext文件

2)使用Microsoft.AspNet.Identity.EntityFramework添加命名空间;

3) public MyDbContext（）： base（“name=MyDbContext”） { Database.SetInitializer（new DropCreateDatabaseAlways（））; }

2015-09-29 07:19:33

自数据库创建以来，支持<Database>上下文的模型已经更改

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