Following is a table creating script created by Entity Framework using the model shown in https://codereview.stackexchange.com/questions/14077/is-it-proper-tpt-inheritance.
In this script, there are two alter statements. What is the need for the second ALTER statement?
SCRIPT
CREATE TABLE [dbo].[SellingItems_Book](
[Title] [nvarchar](max) NULL,
[Id] [int] NOT NULL,
CONSTRAINT [PK_SellingItems_Book] 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]
GO
First Alter
ALTER TABLE [dbo].[SellingItems_Book] WITH CHECK ADD CONSTRAINT [FK_Book_inherits_SellingItem] FOREIGN KEY([Id])
REFERENCES [dbo].[SellingItems] ([Id])
GO
Second Alter
ALTER TABLE [dbo].[SellingItems_Book] CHECK CONSTRAINT [FK_Book_inherits_SellingItem]
GO