A primary key. Two foreign keys,
Change the two foreign keys to non-empty on the line.
CREATE TABLE [dbo].[User_compare]( [Id] [int] IDENTITY(1,1) not NULL, [UserId] [int] not NULL, [Patentid] [int] not NULL, CONSTRAINT [Pk_user_compare] PRIMARY KEY CLUSTERED ( [Id] ASC) with(Pad_index= OFF, Statistics_norecompute= OFF, Ignore_dup_key= OFF, Allow_row_locks= on, Allow_page_locks= on) on [PRIMARY]) on [PRIMARY]GOALTER TABLE [dbo].[User_compare] with CHECK ADD CONSTRAINT [fk_user_compare_patents] FOREIGN KEY([Patentid])REFERENCES [dbo].[Patents]([Id])GOALTER TABLE [dbo].[User_compare] CHECK CONSTRAINT [fk_user_compare_patents]GOALTER TABLE [dbo].[User_compare] with CHECK ADD CONSTRAINT [fk_user_compare_users] FOREIGN KEY([UserId])REFERENCES [dbo].[Users]([Id])GOALTER TABLE [dbo].[User_compare] CHECK CONSTRAINT [fk_user_compare_users]GO
You cannot insert an explicit value error resolution to an identity column in a table when IDENTITY_INSERT is set to OFF