資料字典產生器

CREATE TABLE customers (
    id          bigserial PRIMARY KEY,
    email       varchar(255) NOT NULL UNIQUE,
    full_name   varchar(120),
    created_at  timestamptz  NOT NULL DEFAULT now()
);
COMMENT ON TABLE customers IS '已註冊的顧客；每人一列';
COMMENT ON COLUMN customers.email IS '登入用電子郵件，全站唯一';

CREATE TABLE products (
    id        bigserial     PRIMARY KEY,
    sku       varchar(40)   NOT NULL UNIQUE,
    title     varchar(200)  NOT NULL,
    price     numeric(10,2) NOT NULL,
    stock     int           NOT NULL DEFAULT 0
);
COMMENT ON TABLE products IS '商品目錄；已下架的商品仍保留 SKU';
COMMENT ON COLUMN products.stock IS '庫存數量，由倉儲同步更新';

CREATE TABLE orders (
    id           bigserial     PRIMARY KEY,
    customer_id  bigint        NOT NULL REFERENCES customers(id),
    status       varchar(20)   NOT NULL DEFAULT 'pending',
    total        numeric(10,2) NOT NULL,
    placed_at    timestamptz   NOT NULL DEFAULT now()
);
COMMENT ON COLUMN orders.status IS 'pending -> paid -> shipped -> done，或 cancelled';

CREATE TABLE order_items (
    order_id    bigint        NOT NULL REFERENCES orders(id),
    product_id  bigint        NOT NULL REFERENCES products(id),
    qty         int           NOT NULL,
    unit_price  numeric(10,2) NOT NULL,
    PRIMARY KEY (order_id, product_id)
);
COMMENT ON TABLE order_items IS '訂單明細；單價在購買當下固定';

CREATE TABLE shipments (
    id         bigserial   PRIMARY KEY,
    order_id   bigint      NOT NULL REFERENCES orders(id),
    carrier    varchar(60) NOT NULL,
    tracking   varchar(80),
    shipped_at timestamptz
);

CREATE INDEX idx_orders_customer ON orders(customer_id);
CREATE INDEX idx_shipments_order ON shipments(order_id);