放置Database.SetInitializer [英] Place to put Database.SetInitializer

问题描述

我正在开发一个项目，最终可以使用多个UI版本/变体，但到目前为止，我的解决方案Web中有两个子项目 - 包含ASP.NET MVC的Web界面。服务项目是我有数据库上下文和模型定义的地方。

我的目标是在我的Web项目中对EF特定代码进行最少或可能没有引用。我希望它是独立的，所以当我用服务后端切换dll（从让我们说SQL到XML或MySQL）我不应该在我的MVC项目中进行多个修改。

这是它的外观：

我的问题是：
- 到目前为止，我没有发现使用数据库的例子。 SetInitializer位于Global.asax之外。如果我的工厂类型的DatabaseContextProvider类或服务类中的模型发生变化，我想将数据库重新创建，从上下文中提取数据，并将其提供给具有DTO的UI。这个位置有什么缺点吗？
- 我想使上下文的connectionString可以使用Properties / Settings.settings文件进行配置 - 是否合理？

解决方案

在第一次使用 DbContext 之前，您将需要一种调用 Database.SetInitializer 方法的机制。这就是为什么它通常在 Global.asax 文件中调用。

您可以使用初始化方法创建一个类在 tm.Service 项目中，并在 Application_Start 方法中调用它，并放入数据库。 SetInitializer 在该初始化方法中。

它可以从设置文件提供连接字符串。

I'm working on a project that at can end up with multiple UI versions / variants, but so far I've got two subprojects in my solution Web - containing Web interface with ASP.NET MVC. Service project is place where I have my database context and models defined.

My Goal is to have minimum or possibly no references to EF specific code in my Web project. I want it to be independent so when I switch the dlls with service backend ( from let say SQL to XML or MySQL ) I shouldn't make multiple modifications in my MVC project.

This is how it looks :

My Questions are: - so far I've found no example of using Database.SetInitializer in other place than Global.asax. I'd like to put database re-creation if model changed in my factory-like DatabaseContextProvider class or in service class that pulls out data from context and provides it to the UI with DTOs. Are there any cons of that location ? - I would like to have the context's connectionString to be configurable with Properties/Settings.settings file - is that reasonable ?

解决方案

You would need a mechanism to call the Database.SetInitializer method before the very first usage of the DbContext. That is why its usually called in the Global.asax file.

You can create a class with an initialization method in your tm.Service project and call it in the Application_Start method and put the Database.SetInitializer in that initialization method.

Its OK to supply the connection string from a setting file.

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