一个组件作为外键的复合键

Question

我有一个金融应用程序，我每天都在其中存储行情数据，所以我从 Ticker 和 Date.

创建了一个主键

我还需要将 Ticker（它是上述组合键的一部分）作为另一个 table 的外键，称为 Tickers。

然而，当我在 SQL Server Management Studio 中添加外键关系时，它要求我为 Ticker 和 Date 两列提供 link ，而 Ticker table 只包含 Ticker （这是我只想绑定的内容）。

请问我做错了什么，或者这不可能吗？

我的table如下：

CREATE TABLE [dbo].[Tickers](
    [Ticker] [nvarchar](8) NOT NULL,
    [Name] [nvarchar](50) NOT NULL,
    [Market] [int] NOT NULL,
    [Locale] [int] NOT NULL,
    [Type] [int] NOT NULL,
    [Active] [bit] NOT NULL,
    [PrimaryExch] [nvarchar](50) NOT NULL,
    [Updated] [datetime2](7) NOT NULL,
    [Currency] [int] NOT NULL,
CONSTRAINT [PK_Tickers] PRIMARY KEY CLUSTERED 
(
    [Ticker] 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

CREATE TABLE [dbo].[AggregateDay](
    [Ticker] [nchar](8) NOT NULL,
    [Date] [date] NOT NULL,
    [Volume] [decimal](18, 0) NULL,
    [Open] [decimal](18, 0) NULL,
    [Close] [decimal](18, 0) NULL,
    [High] [decimal](18, 0) NULL,
    [Low] [decimal](18, 0) NULL,
    [Samples] [int] NULL,
 CONSTRAINT [PK_AggregateDay] PRIMARY KEY CLUSTERED 
(
    [Ticker] ASC,
    [Date] 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

Answer 1

您设置的一个问题是父列和子列的数据类型不同：[dbo].[Tickers]([Ticker]) 是 [nvarchar](8)，而 [dbo].[AggregateDay](Ticket) 是 [nchar](8) .

如果对齐两种数据类型，则可以创建关系，如下所示：

CREATE TABLE [dbo].[AggregateDay](
    [Ticker] [nvarchar](8) NOT NULL 
        REFERENCES [dbo].[Tickers]([Ticker]),  -- foreign key declaration
    [Date] [date] NOT NULL,
    [Volume] [decimal](18, 0) NULL,
    [Open] [decimal](18, 0) NULL,
    [Close] [decimal](18, 0) NULL,
    [High] [decimal](18, 0) NULL,
    [Low] [decimal](18, 0) NULL,
    [Samples] [int] NULL,
CONSTRAINT [PK_AggregateDay] PRIMARY KEY CLUSTERED 
    ([Ticker] ASC, [Date] ASC)
    WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) 
    ON [PRIMARY]
) ON [PRIMARY]

Demo on DB Fiddle

一个组件作为外键的复合键

Composite key with one component being a foreign key

sql

database

sql-server

foreign-keys

create-table