使用Model First方法时如何种子数据？ [英] How to seed data when using Model First approach?

问题描述

所以我正在学习MVC3和EF4。
我尝试了代码第一种方法，但是对我来说太混乱了。我可以创建类没有问题，但是处理外键和彼此之间的关系时，硬件部分来了。

但是我已经和模型一起走了。这样，我可以直观地设计它，并查看关系的位置。

在创建模型之后，它将为我创建一个针对我的SQL SQL数据库。完成并完成。

现在我想要我的表中的数据。当然，我可以把它们添加到使用服务器浏览器中，但很可能我会在我的模型中进行更改。并不断更新数据库。所以我不能手动输入数据。我知道如果你先使用代码，你可以导出 DropCreateDatabaseIfModelChanges 并覆盖 seed 方法。

然而，如何使用模型第一种方法来做到这一点？
我有以下代码：

  public class DatabaseInitializer：IDatabaseInitializer< BettingContext> {
 public void InitializeDatabase（BettingContext context）{
 var teams = new List< Team> {
 new Team {Name =Toronto Maple Leafs，League =NHL}，
 new Team {Name =Boston Bruins，League =NHL}，
 new Team {Name =Vancouver Canucks，League =NHL}，
 new Team {Name =Nashville Predators，League =NHL}，
 new Team {Name =Montreal Canadiens League =NHL}，
}; 
} 
} 
  

当然，在我的全局文件中：

  protected void Application_Start（）
 {
 Database.SetInitializer< BettingContext>（new DatabaseInitializer（））; 
 AreaRegistration.RegisterAllAreas（）; 
 
 RegisterGlobalFilters（GlobalFilters.Filters）; 
 RegisterRoutes（RouteTable.Routes）; 
} 
  

那么现在什么？如何告诉它运行方法？我做错了什么？

解决方案

你可以这样做：

public $ MyCode =
{
protected override void Seed（YourDataBaseContextClass context）
{
//在这里创建对象并将其添加到您的上下文DBSets ...

}
}

public class YourDataBaseContextClass：DbContext
{


}

然后，在 Application_Start（）中调用：

  Database.SetInitializer（new MySeedData（））;在您的情况下，您可以尝试手动创建DbSets（使用您的模型的第一类）并尝试插入它使用上面的代码。这是一个混合的Model First + Code First。
  public class FourthCoffeeWebContext：DbContext 
 {
 public DbSet< Category>分类{get;组; } 
 public DbSet< Product>产品{get;组; } 
} 
  
添加到： CreateDatabaseIfNotExists<（Of<（<'TContext>）>）>  
 
So I am learning MVC3 and EF4. 
I tried the code first method but it was too confusing for me.. I can create the classes no problem, but the hard part comes when dealing with foreign keys and the relationships between each other. 

But I've gone with model first. This way I can visually design it and see where the relationships are.

After my model is create, it creates a SQL for me which I execute against my SQL Express database. Done, and done.

Now I want data in my tables. Of course I can just add them in using server explorer, but most likely I will be making changes to my model as I go along. And keep updating the database. So I can't keep manually entering data. I know if you use code first you can derive the DropCreateDatabaseIfModelChanges and override the seed method. 

However how do I do this with model first approach? 
I have the following code:
 public class DatabaseInitializer : IDatabaseInitializer<BettingContext> {
    public void InitializeDatabase(BettingContext context) {
        var teams = new List<Team> {
            new Team { Name="Toronto Maple Leafs", League="NHL"},
            new Team { Name="Boston Bruins", League="NHL"},
            new Team { Name="Vancouver Canucks", League="NHL"},
            new Team { Name="Nashville Predators", League="NHL"},
            new Team { Name="Montreal Canadiens", League="NHL"},
        };
    }
}
Of course and in my global file: 
protected void Application_Start()
{
    Database.SetInitializer<BettingContext>(new DatabaseInitializer());
    AreaRegistration.RegisterAllAreas();

    RegisterGlobalFilters(GlobalFilters.Filters);
    RegisterRoutes(RouteTable.Routes);
}
so now what? How do I tell it to run the method? What am I doing wrong?
解决方案
You can have something like this:
public class MySeedData : DropCreateDatabaseIfModelChanges<YourDataBaseContextClass>
{
    protected override void Seed(YourDataBaseContextClass context)
    {  
       // Create objects here and add them to your context DBSets...

    }
}

public class YourDataBaseContextClass : DbContext
{


}
Then, within Application_Start() you call:
Database.SetInitializer(new MySeedData());
In your case, you could try creating DbSets (using your model first classes) manually and try to plug it using the code above. It's kind of a mix of Model First + Code First.
public class FourthCoffeeWebContext : DbContext
{
    public DbSet<Category> Categories { get; set; }
    public DbSet<Product> Products { get; set; }
}
Adding to this: CreateDatabaseIfNotExists<(Of <(<'TContext>)>)>

                        
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