外键到复合键

Foreign key to composite key(外键到复合键)

问题描述

我有一个问题，我需要将单个外键引用到另一个表中的复合键.

I have a problem i need to reference a single foreign key to a composite key in another table.

我的数据库结构如下:

CREATE TABLE available_trip (
trip_code integer not null,
date datetime not null,
primary key(trip_code, date),
FOREIGN KEY (trip_code) REFERENCES trip (trip_code)
);

CREATE TABLE booking (
    available_trip_code integer not null,
    customer_code integer not null,
    date datetime not null,
    deposit float not null,
    total_price float not null,
    has_paid float not null,
    description_en nvarchar(12) null,
    finance_type_code nvarchar(12) not null,
    primary key(available_trip_code, customer_code, date),
    FOREIGN KEY (available_trip_code) REFERENCES available_trip (trip_code, date),


FOREIGN KEY (customer_code) REFERENCES customer (customer_code),
            FOREIGN KEY (finance_type_code) REFERENCES finance_type (finance_type_code)
        );

我的问题是:我如何让 booking.available_trip_code 引用 available_trip.trip_code 和 available_trip.date ?

my question is: how do I let booking.available_trip_code reference to available_trip.trip_code and available_trip.date ?

推荐答案

如果您引用复合主键，您的外键也需要包含所有这些列 - 所以您需要类似:

If you reference a composite primary key, your foreign key also needs to contain all those columns - so you need something like:

FOREIGN KEY (available_trip_code, date) 
            REFERENCES available_trip (trip_code, date)

如果您的表中还没有所有这些列，则需要添加它们.

If you don't already have all those columns present in your table, then you'll need to add them.

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