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Update alter_northwind.sql #78

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Update alter_northwind.sql #78

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18 changes: 15 additions & 3 deletions homework-4/alter_northwind.sql
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Original file line number Diff line number Diff line change
@@ -1,12 +1,24 @@
-- Подключиться к БД Northwind и сделать следующие изменения:
-- 1. Добавить ограничение на поле unit_price таблицы products (цена должна быть больше 0)

ALTER TABLE products
ADD CONSTRAINT unit_price_check CHECK (unit_price > 0);

-- 2. Добавить ограничение, что поле discontinued таблицы products может содержать только значения 0 или 1

ALTER TABLE products
ADD CONSTRAINT discontinued_check CHECK (discontinued IN (0, 1));

-- 3. Создать новую таблицу, содержащую все продукты, снятые с продажи (discontinued = 1)

CREATE TABLE discontinued_products AS
SELECT *
FROM products
WHERE discontinued = 1;

-- 4. Удалить из products товары, снятые с продажи (discontinued = 1)
-- Для 4-го пункта может потребоваться удаление ограничения, связанного с foreign_key. Подумайте, как это можно решить, чтобы связь с таблицей order_details все же осталась.
ALTER TABLE order_details
DROP CONSTRAINT fk_order_details_product_id;
DELETE FROM products
WHERE discontinued = 1;
ALTER TABLE order_details
ADD CONSTRAINT fk_order_details_product_id
FOREIGN KEY (product_id) REFERENCES products(product_id);