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问题描述
在我的数据库中，我有一个带有主键的 Vehicle 表。我正在使用
new Vehicle（）创建一个新的车辆
并适当更新车辆的属性。
当我尝试做一个
genesisContext.Vehicles.AddObject （车辆）;
表首次成功更新，主键为0.在以后的任何时候，我得到一个错误，说密钥不是唯一的
(presumably because the primary key set by the EF is still 0)
I was under the understanding that the EF intelligently works out primary keys so why is this happening??
解决方案
You have two choices:
- either you let the database handle the primary key, by specifying the VehicleID as
INT IDENTITY(1,1)- in that case, SQL Server will automagically assign unique and individual numbers, and EF will be fine with that - or you handle it yourself, e.g. you have to find a way in your app to come up with unique vehicle ID numbers.
EF out of the box has nothing in it to magically dispense unique numbers for primary keys - if you thought that, it was a misconception.
Marc
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