在 SQL Server 2008 上设置实体框架代码优先数据库
我使用 SQL Server CE 成功创建了我的第一个实体框架代码优先项目。数据库表是自动创建的，一切都很好。
然后，我更改了连接字符串以指向我创建的 SQL Server 数据库，并期望它自动生成表。它没有，而是抱怨表不存在。
经过一番阅读后，我发现我需要向我的 App_Start 方法添加一个初始化程序。
我尝试过：
// Method 1
Database.SetInitializer(new DropCreateDatabaseIfModelChanges<EFContext>());
但这一开始不起作用，因为它找不到 EdmMetaData 表来发现模型是否已更改。
所以我尝试添加：
// Method 2
Database.SetInitializer(new CreateDatabaseIfNotExists<EFContext>());
但这不起作用，因为我已经创建了数据库，当我删除数据库时，它仍然不起作用，因为我登录的用户没有创建数据库权限。
我终于尝试了：
// Method 3
Database.SetInitializer(new DropCreateDatabaseAlways<EFContext>());
哪个有效，但我真的不想每次都删除数据库。因此，一旦它运行并添加了 EdmMetaData 表，我就用方法 1 替换了它，现在效果很好。
虽然这个方法可行，但是感觉不像我使用 SQL Server CE 时那么优雅，而且我还没有发现有人建议你使用这个方法。
那么，我是否遗漏了一些东西，有没有一种更简单、更优雅的方法来做到这一点？
I successfully created my first Entity Framework Code first project using SQL Server CE. The database tables were created automatically and all was well.
I then changed my connection string to point to a SQL Server database I'd created and expected it to autogenerate the tables. It didn't and instead complained about the tables not existing.
After some reading I found that I needed to add an initializer to my App_Start method.
I tried:
// Method 1
Database.SetInitializer(new DropCreateDatabaseIfModelChanges<EFContext>());
But this didn't work at first because it couldn't find an EdmMetaData table to discover if the model had changed.
So I tried adding:
// Method 2
Database.SetInitializer(new CreateDatabaseIfNotExists<EFContext>());
But this didn't work because I'd already created the database, and when I removed the database it still didn't work because the user I was logging in as didn't have create database privileges.
I finally tried:
// Method 3
Database.SetInitializer(new DropCreateDatabaseAlways<EFContext>());
Which worked, but I don't really want to drop the db every time. So once it ran and added the EdmMetaData table I replaced it with method 1 and that now works fine.
Although this method works, it doesn't feel as elegant as when I was using SQL Server CE and I've not found someone suggesting that you use this method.
So, am I missing something and is there an easier, more elegant way to do this?
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方法 1 和 2 要求数据库尚不存在。如果您手动创建数据库，它们将不起作用。如果您需要 EF 在现有数据库中创建表，则必须创建 自定义数据库初始值设定项。
Method 1 and 2 expects that database doesn't exist yet. They don't work if you create database manually. If you need EF to create tables in existing database you must create custom database initializer.