Add sql cript

proiz_pract_script.sql

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+CREATE TABLE TourFirm (
+    firm_id      SERIAL PRIMARY KEY,
+    firm_name    VARCHAR(100) NOT NULL,
+    people_count INT          NOT NULL CHECK (people_count > 0)
+); 
+CREATE TABLE RoomType (
+    room_type_id SERIAL PRIMARY KEY,
+    type_name    VARCHAR(50) NOT NULL UNIQUE
+); 
+CREATE TABLE Room (
+    room_id      SERIAL PRIMARY KEY,
+    room_type_id INT          NOT NULL REFERENCES RoomType(room_type_id)
+                                ON DELETE RESTRICT ON UPDATE CASCADE,
+    room_number  INT          NOT NULL UNIQUE CHECK (room_number > 0),
+    occupancy    INT          NOT NULL CHECK (occupancy > 0),
+    rating       DECIMAL(3,1) NOT NULL DEFAULT 0.0
+                               CHECK (rating >= 0.0 AND rating <= 5.0)
+); 
+CREATE TABLE Client (
+    client_id    SERIAL PRIMARY KEY,
+    firm_id      INT         NOT NULL REFERENCES TourFirm(firm_id)
+                               ON DELETE RESTRICT ON UPDATE CASCADE,
+    last_name    VARCHAR(60) NOT NULL,
+    first_name   VARCHAR(60) NOT NULL,
+    patronymic   VARCHAR(60),
+    phone_number VARCHAR(20) NOT NULL
+);
+CREATE TABLE Booking (
+    booking_id     SERIAL PRIMARY KEY,
+    client_id      INT          NOT NULL REFERENCES Client(client_id)
+                                  ON DELETE RESTRICT ON UPDATE CASCADE,
+    room_id        INT          NOT NULL REFERENCES Room(room_id)
+                                  ON DELETE RESTRICT ON UPDATE CASCADE,
+    check_in_date  DATE         NOT NULL,
+    check_out_date DATE         NOT NULL,
+    price_per_night DECIMAL(10,2) NOT NULL CHECK (price_per_night > 0),s
+    CHECK (check_out_date > check_in_date)
+); 
+CREATE TABLE Service (
+    service_id   SERIAL PRIMARY KEY,
+    service_name VARCHAR(100) NOT NULL UNIQUE
+);
+CREATE TABLE RoomTypeService (
+    room_type_id INT NOT NULL REFERENCES RoomType(room_type_id)
+                       ON DELETE RESTRICT ON UPDATE CASCADE,
+    service_id   INT NOT NULL REFERENCES Service(service_id)
+                       ON DELETE RESTRICT ON UPDATE CASCADE,
+    PRIMARY KEY (room_type_id, service_id)
+);
+
+SELECT * FROM booking
+
+--Расчетный атрибут — итоговая стоимость бронирования
+--total_cost = price_per_night * (check_out_date - check_in_date)
+
+ 
+CREATE OR REPLACE VIEW BookingCostView AS
+SELECT
+    b.booking_id,
+    c.last_name || ' ' || c.first_name || ' ' || COALESCE(c.patronymic, '') AS client_full_name,
+    r.room_number,
+    rt.type_name                                               AS room_type,
+    b.check_in_date,
+    b.check_out_date,
+    (b.check_out_date - b.check_in_date)                      AS nights,
+    b.price_per_night,
+    b.price_per_night * (b.check_out_date - b.check_in_date)  AS total_cost
+FROM Booking b
+JOIN Client   c  ON c.client_id     = b.client_id
+JOIN Room     r  ON r.room_id       = b.room_id
+JOIN RoomType rt ON rt.room_type_id = r.room_type_id;
+
+
+--Проверочный запрос
+
+SELECT * FROM BookingCostView ORDER BY total_cost DESC LIMIT 10;
+
+
+--Возвращает итоговую стоимость конкретного бронирования
+--Использование в приложении: при отображении карточки брони
+
+
+CREATE OR REPLACE FUNCTION get_booking_cost(p_booking_id INT)
+RETURNS DECIMAL(10,2)
+LANGUAGE plpgsql
+AS $$
+DECLARE
+    v_cost DECIMAL(10,2);
+BEGIN
+    SELECT price_per_night * (check_out_date - check_in_date)
+    INTO v_cost
+    FROM Booking
+    WHERE booking_id = p_booking_id;
+
+    IF NOT FOUND THEN
+        RAISE EXCEPTION 'Бронирование с ID % не найдено', p_booking_id;
+    END IF;
+
+    RETURN v_cost;
+END;
+$$;
+
+SELECT get_booking_cost(2);
+
+
+
+-- Создаёт новое бронирование
+
+CREATE OR REPLACE PROCEDURE create_booking(
+    p_client_id      INT,
+    p_room_id        INT,
+    p_check_in_date  DATE,
+    p_check_out_date DATE,
+    p_price_per_night DECIMAL(10,2)
+)
+LANGUAGE plpgsql
+AS $$
+BEGIN
+    IF p_check_out_date <= p_check_in_date THEN
+        RAISE EXCEPTION 'Дата выезда должна быть позже даты заезда';
+    END IF;
+	
+    IF NOT EXISTS (SELECT 1 FROM Client WHERE client_id = p_client_id) THEN
+        RAISE EXCEPTION 'Клиент с ID % не найден', p_client_id;
+    END IF;
+
+    IF NOT EXISTS (SELECT 1 FROM Room WHERE room_id = p_room_id) THEN
+        RAISE EXCEPTION 'Комната с ID % не найдена', p_room_id;
+    END IF;
+	
+    IF EXISTS (
+        SELECT 1 FROM Booking
+        WHERE room_id = p_room_id
+          AND check_in_date  < p_check_out_date
+          AND check_out_date > p_check_in_date
+    ) THEN
+        RAISE EXCEPTION 'Комната % уже забронирована на указанные даты', p_room_id;
+    END IF;
+	
+    INSERT INTO Booking (client_id, room_id, check_in_date, check_out_date, price_per_night)
+    VALUES (p_client_id, p_room_id, p_check_in_date, p_check_out_date, p_price_per_night);
+	
+    RAISE NOTICE 'Бронирование успешно создано для клиента ID %', p_client_id;
+END;
+$$;
+
+
+CALL create_booking(3, 5, '2026-03-01', '2026-03-014', 2500.00);
+
+SELECT setval('tourfirm_firm_id_seq',   (SELECT MAX(firm_id)      FROM TourFirm));
+SELECT setval('client_client_id_seq',   (SELECT MAX(client_id)    FROM Client));
+SELECT setval('room_room_id_seq',        (SELECT MAX(room_id)      FROM Room));
+SELECT setval('roomtype_room_type_id_seq',(SELECT MAX(room_type_id) FROM RoomType));
+SELECT setval('service_service_id_seq', (SELECT MAX(service_id)   FROM Service));
+SELECT setval('booking_booking_id_seq', (SELECT MAX(booking_id)   FROM Booking));
+
+--Логирование бронирований
+
+CREATE TABLE AuditLog (
+    log_id    SERIAL PRIMARY KEY,
+    tbl_name  VARCHAR(50),
+    action    VARCHAR(10),
+    changed_at TIMESTAMP DEFAULT NOW(),
+    old_data  JSONB,
+    new_data  JSONB
+);
+
+CREATE OR REPLACE FUNCTION audit_booking()
+RETURNS TRIGGER LANGUAGE plpgsql AS $$
+BEGIN
+    INSERT INTO AuditLog (tbl_name, action, old_data, new_data)
+    VALUES (
+        TG_TABLE_NAME, TG_OP,
+        CASE WHEN TG_OP = 'DELETE' THEN row_to_json(OLD)::jsonb ELSE NULL END,
+        CASE WHEN TG_OP != 'DELETE' THEN row_to_json(NEW)::jsonb ELSE NULL END
+    );
+    RETURN NEW;
+END;
+$$;
+
+CREATE TRIGGER trg_audit_booking
+AFTER INSERT OR UPDATE OR DELETE ON Booking
+FOR EACH ROW EXECUTE FUNCTION audit_booking();