SQL设置主键和自增长列

CREATE TABLE [dbo].[ThirdPro]
(
  Id INT NOT NULL
          IDENTITY(1, 1)
          PRIMARY KEY ,
  [ProID] UNIQUEIDENTIFIER NULL ,
  [PartType] VARCHAR(500) NULL
)

ALTER TABLE ThirdPrice
DROP COLUMN Id

ALTER TABLE ThirdPrice ADD Id INT NOT NULL IDENTITY(1,1)

ALTER TABLE ThirdPro
ADD CONSTRAINT PK_Id PRIMARY KEY (Id)

ALTER TABLE ThirdPro
DROP CONSTRAINT PK_Id PRIMARY KEY (Id)