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Views triggers
Views Triggers A view trigger is a special type of trigger that is executed automatically when a row is inserted, updated, or deleted in a related table....
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Views Triggers A view trigger is a special type of trigger that is executed automatically when a row is inserted, updated, or deleted in a related table....
A view trigger is a special type of trigger that is executed automatically when a row is inserted, updated, or deleted in a related table. This allows you to implement complex logic or perform specific actions without directly modifying the underlying tables.
Key features of view triggers:
They are defined using the CREATE VIEW statement, not the CREATE TRIGGER statement.
They do not affect the underlying tables, but rather, they define a virtual table based on the specified tables and relationships.
They can contain complex SQL statements, including SELECTs, FROMs, WHERE clauses, and other triggers.
They can be used to enforce business rules, maintain data integrity, or perform other tasks that need to be performed automatically.
Examples:
sql
CREATE VIEW customer_orders AS
SELECT customer_id, COUNT(*) AS order_count
FROM orders
GROUP BY customer_id;
sql
CREATE VIEW product_prices AS
SELECT category_id, AVG(price) AS average_price
FROM products
WHERE category_id = 1;
sql
CREATE VIEW discounted_products AS
SELECT p.id, p.price, p.discount
FROM products p
LEFT JOIN discounts d
ON p.id = d.product_id
WHERE d.discount_percentage > 10;
These are just a few basic examples. View triggers offer a powerful mechanism for implementing complex data manipulation and security tasks in a database system