每个继承类一个表

1、每个继承一个表场景，适用与主表及主表扩展表情景

　　主表与扩展表是1：0...1关系。

每个继承类一个表

2.创建表

CREATE TABLE [Chapter2].[Business](
    [BusinessId] [int] IDENTITY(1,1) primary key,
    [Name] [varchar](50) NOT NULL,
    [LicenseNumber] [varchar](20) NOT NULL
    )
GO

CREATE TABLE [Chapter2].[eCommerce](
    [BusinessId] [int] PRIMARY Key ,
    [URL] [varchar](1024) NULL
)


ALTER TABLE [Chapter2].[eCommerce]  WITH CHECK ADD  CONSTRAINT [FK_eCommerce_Business] FOREIGN KEY([BusinessId])
REFERENCES [Chapter2].[Business] ([BusinessId])
GO

GO


CREATE TABLE [Chapter2].[Retail](
    [BusinessId] [int] NOT NULL,
    [Address] [varchar](50) NOT NULL,
    [City] [varchar](50) NOT NULL,
    [State] [varchar](2) NOT NULL,
    [ZIPCode] [varchar](9) NOT NULL
    )
GO

ALTER TABLE [Chapter2].[Retail]  WITH CHECK ADD  CONSTRAINT [FK_Retail_Business] FOREIGN KEY([BusinessId])
REFERENCES [Chapter2].[Business] ([BusinessId])
GO

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