DbMigrationsConfiguration与EF中的DbMigration有何关系

问题描述

在Entity Framework中，通过使用 Enable-Migrations 创建一个 Migrations 文件夹，其中包含 Configuration 继承自 DbMigrationsConfiguration ，像这样：

In Entity Framework by using Enable-Migrations a Migrations folder is created containing a Configuration inherited from DbMigrationsConfiguration like this:

internal sealed class Configuration : DbMigrationsConfiguration<MyDbContext>
{
    ...
}

所有已创建的迁移使用 Add-Migration 创建的文件也放置在 Migrations 文件夹中。

All the created migrations which are created using Add-Migration are placed in the Migrations folder too.

public partial class Init: DbMigration
{
    public override void Up()
    {
        ...
    }

    public override void Down()
    {
        ...
    }
}

我没有找到任何将这两者联系在一起的代码（例如，在迁移中具有配置属性）。我发现的唯一关系是两者都放在同一文件夹中。如果我有1个以上的 DbContext ，因此有1个以上的配置，我想知道如何区分这些 DbMigration ？

I didn't find any code that relates these two together ( for example having a configuration property in migrations). The only relation I found is that both are placed in same folder. If I have more than 1 DbContext and consequently more than 1 Configuration, I'm wondering how these DbMigrations are distinguished?

问题： DbMigration 类与配置？

推荐答案

它们按照惯例相互关联。默认情况下，它将迁移存储在名为迁移的根文件夹中。您可以在配置的构造函数（），或者在您enable-migrations：

They are related by convention. By default, it will store the migrations in a root folder called Migrations. You can override this in the constructor of the config (https://msdn.microsoft.com/en-us/library/system.data.entity.migrations.dbmigrationsconfiguration(v=vs.113).aspx) or when you enable-migrations:

public Configuration()
{
    AutomaticMigrationsEnabled = true;
    MigrationsDirectory = @"Migrations\Context1";
}

对于多个上下文，请使用-Co​​ntextTypeName为每个上下文创建不同的配置和文件夹ProjectName.Models.Context2 -MigrationsDirectory：迁移\Context2。这是一个演练：

For multiple contexts, create a different config and folder for each by using -ContextTypeName ProjectName.Models.Context2 -MigrationsDirectory:Migrations\Context2. Here is a walkthrough: http://www.dotnettricks.com/learn/entityframework/entity-framework-6-code-first-migrations-with-multiple-data-contexts

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