组合键的外键 [英] Foreign key to composite key
本文介绍了组合键的外键的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我的数据库结构如下所示:
CREATE TABLE available_trip(
trip_code integer not null,
datetime not null,
primary key(trip_code,日期),
FOREIGN KEY(trip_code)REFERENCES trip(trip_code)
);
CREATE TABLE预订(
available_trip_code整数不为空,
客户代码整数不为空,
日期时间不为空,
存款不为空,
total_price float not null,
has_paid float not null,
description_en nvarchar(12)null,
finance_type_code nvarchar(12)非空,
主键(available_trip_code,customer_code, (customer_code),
FOREIGN KEY(customer_code),
FOREIGN KEY(available_trip_code)参考文献available_trip(trip_code,date),
FOREIGN KEY finance_type_code)参考文献finance_type(finance_type_code)
);
我的问题是:如何让 booking.available_trip_code
引用 available_trip.trip_code
和 available_trip.date
?
$ b $ =h2_lin>解决方案
b
FOREIGN KEY(available_trip_code,date)
REFERENCES available_trip(trip_code,date)
如果您的表格中没有列出所有这些列,那么您需要添加它们。
I have a problem i need to reference a single foreign key to a composite key in another table.
My database structure is as following:
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)
);
my question is: how do I let booking.available_trip_code
reference to available_trip.trip_code
and available_trip.date
?
解决方案
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)
If you don't already have all those columns present in your table, then you'll need to add them.
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