如何准备数据库以从中生成 EF 模型
我对如何在关系数据库结构中表示我的对象有一些误解。
例如，如果我有一个简单的表结构，如下所示：
如果我生成实体框架模型基于此，它看起来像：
正如您所看到的，它是多对多关联。 （任何菜肴都包含许多配料，任何配料都可以在许多菜肴中使用）
现在，如果我需要一些额外的参数，例如菜肴中配料的数量，该怎么办？ （当然，任何不同菜肴中的每种成分通常都有不同的编号）。
如果我直接向 Dish_FooIngridient 表添加一些附加列，则会破坏自动模型生成的准确性，然后我必须在 EF 模型设计器中手动修复关联，然后使用一些繁琐的查询来操作对象。因为它会生成成这样的东西：
正如你所看到的，现在还有其他多余的属性，我不需要。有没有更好的方法来管理它？也许使用复杂的属性或继承的实体，或者其他什么？
I have some misunderstanding how my objects should be represented in a relational db structure.
For example if I have a simple tables structure that looks like that:
And if I generate an Entity Framework model based on that, it would be look like:
As you can see it's many-to-many association. (Any Dish contains many Ingredients, any Ingredient can be used in many Dishes)
Now, what if I need some additional parameters, like quantity of the Ingredient in a Dish? (Of course it usually would be distinct number for each ingredient in any different Dish).
If I add some additional columns directly to Dish_FooIngridient table, it breaks nicety of automatic model generation, and then I have to fix associations manually in EF model designer and later use some cumbersome queries to operate with objects. Because it will be generated into something like this:
As you can see, now there are other redundant properties, which I don't need. Is there any better way to manage that? Maybe using complex properties or inherited entity, or something else?
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正如 Apress 的“Entity Framework 4.0 Recipes”中所建议的，设计没有负载的多对多关系并不是一个很好的实践。
As it's suggested in Apress' "Entity Framework 4.0 Recipes", designing Many-To-Many Relationships without a payload not a very good practice.
我不明白为什么。将字段添加到 Dish_FoodIngredient 并为其指定主键。将该表添加到您的模型中即可。您可能需要在代码中进行一些重构，但不要为此责怪 EF。
I don't see why. Add the fields to Dish_FoodIngredient and give it a primary key. Add that table to your model and thats' it. You need to do some refactoring in your code probably but don't blame EF for that.
双击 Model.edmx 文件，然后在对象旁边的空白处右键单击并单击“从数据库更新模型...”，然后单击“完成”，它将刷新您的表。
Double-click your Model.edmx file, then in the white space next to your objects, right-click and click "Update Model from Database...", then click Finish, and it'll refresh your tables.