c# - ‘帮助’ 服务器无法生成主键列

Question

我的创建表代码如下:

CREATE TABLE [dbo].[DeTai](
[ID] [int] IDENTITY(1,1) NOT NULL,
[MaDeTai]  AS ('DT'+right('000000'+CONVERT([varchar](10),[ID]),(6))) PERSISTED NOT NULL,
[TenDeTai] [nvarchar](255) NOT NULL,
[LinhVuc] [nvarchar](255) NOT NULL,
[Nam] [int] NOT NULL,
[MaGV] [varchar](8) NOT NULL,
)

当我使用 linq to sql 插入值时，会出现此消息

The primary key column of type 'VarChar(8)' cannot be generated by the server.

我该怎么办？

Answer 1

你必须指定主键，仅设置身份是不够的

CREATE TABLE [dbo].[DeTai](
  [ID] [int] IDENTITY(1,1) NOT NULL,
  [MaDeTai]  AS ('DT'+right('000000'+CONVERT([varchar](10),[ID]),(6))) PERSISTED NOT NULL,
  [TenDeTai] [nvarchar](255) NOT NULL,
  [LinhVuc] [nvarchar](255) NOT NULL,
  [Nam] [int] NOT NULL,
  [MaGV] [varchar](8) NOT NULL,

  constraint PK_DeTail_ID primary key (ID)
)