视图和实体框架 [英] Views and Entity Framework

问题描述

我已经在数据库中创建了一个视图，希望将其包含在实体模型中。但是，当我尝试通过VS 2008更新实体模型时，出现一条警告消息，通知我我要添加的表或视图没有主键。

I've created a view in my database which I would like to include in my entity model. However, when I try to update the entity model through VS 2008, a warning message informs me that the TABLE OR VIEW I'm trying to add doesn't have a primary key.

似乎要向模型添加视图，必须有一个关键字段！如果不允许视图具有关键字段（至少在我正在使用的DBMRS的firebird中），如何将该视图添加到模型中。

It seems that in order to add a view to the model, this must have a key field! How can I add this view to my model if views are not permitted to have key field, at least in firebird which is the DBMRS I’m using.

任何想法

推荐答案

这里有一个很好的答案：实体框架和SQL Server视图（请参见已接受的答案： https://stackoverflow.com/a/2715299/53510 。）

There's a great answer to that here: Entity Framework and SQL Server View (see accepted answer: https://stackoverflow.com/a/2715299/53510.)

EF通过将所有非可为空的字段。您可以使用ISNULL和NULLIF来操纵视图列的可为空性，从而迫使EF选择所需的PK。

EF infers a PK for views by combining all non-nullable fields. You can use ISNULL and NULLIF to manipulate the nullability of view columns thereby forcing EF to pick the PK you want.

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