问题
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.
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.
Any idea of how to solve this?
回答1:
There's a great answer to that here: Entity Framework and SQL Server View (see accepted answer: https://stackoverflow.com/a/2715299/53510.)
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.
回答2:
There is no keys in firebird views. Instead, set one (or more) field as 'not null' with the following command:
update RDB$RELATION_FIELDS set RDB$NULL_FLAG = 1 where (RDB$FIELD_NAME = 'A_FIELD') and (RDB$RELATION_NAME = 'A_VIEW')
Then re-import the database in entity framework.
来源：https://stackoverflow.com/questions/1234088/views-and-entity-framework