Включена ли автофиксация по умолчанию в MySQL?

-- Simple view
CREATE VIEW active_customers AS
SELECT id, name, email FROM customers WHERE status = 'active';

-- Complex view with joins
CREATE VIEW order_summary AS
SELECT 
    o.id AS order_id,
    c.name AS customer_name,
    SUM(oi.quantity * oi.price) AS total
FROM orders o
JOIN customers c ON o.customer_id = c.id
JOIN order_items oi ON o.id = oi.order_id
GROUP BY o.id, c.name;

-- Query it like a table
SELECT * FROM order_summary WHERE total > 1000;

-- Materialized view (PostgreSQL) — stores actual data, needs refresh
CREATE MATERIALIZED VIEW monthly_sales AS
SELECT DATE_TRUNC('month', order_date) AS month, SUM(total) 
FROM orders GROUP BY 1;

REFRESH MATERIALIZED VIEW monthly_sales;

-- MySQL Stored Procedure
DELIMITER //
CREATE PROCEDURE TransferMoney(
    IN from_account INT,
    IN to_account INT,
    IN amount DECIMAL(10,2)
)
BEGIN
    DECLARE EXIT HANDLER FOR SQLEXCEPTION
    BEGIN
        ROLLBACK;
        RESIGNAL;
    END;
    
    START TRANSACTION;
    UPDATE accounts SET balance = balance - amount WHERE id = from_account;
    UPDATE accounts SET balance = balance + amount WHERE id = to_account;
    COMMIT;
END //
DELIMITER ;

-- Call it
CALL TransferMoney(1, 2, 100.00);

-- Audit trigger: log all salary changes
CREATE TRIGGER trg_salary_audit
AFTER UPDATE ON employees
FOR EACH ROW
BEGIN
    IF OLD.salary <> NEW.salary THEN
        INSERT INTO salary_audit (emp_id, old_salary, new_salary, changed_at)
        VALUES (NEW.id, OLD.salary, NEW.salary, NOW());
    END IF;
END;

-- Trigger types:
-- BEFORE INSERT/UPDATE/DELETE → Validate/modify data before it hits the table
-- AFTER  INSERT/UPDATE/DELETE → Log, cascade, notify
-- INSTEAD OF (views only)     → Redirect operations

-- MySQL cursor example
DELIMITER //
CREATE PROCEDURE ProcessEmployees()
BEGIN
    DECLARE done INT DEFAULT FALSE;
    DECLARE emp_name VARCHAR(100);
    DECLARE emp_salary DECIMAL(10,2);
    
    DECLARE emp_cursor CURSOR FOR 
        SELECT name, salary FROM employees WHERE department = 'Sales';
    DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;
    
    OPEN emp_cursor;
    read_loop: LOOP
        FETCH emp_cursor INTO emp_name, emp_salary;
        IF done THEN LEAVE read_loop; END IF;
        -- Process each row here
    END LOOP;
    CLOSE emp_cursor;
END //
DELIMITER ;