CREATE TABLE customer (
    id TEXT PRIMARY KEY,
    name TEXT NOT NULL
);

CREATE TABLE sales_order (
    id TEXT PRIMARY KEY,
    order_number TEXT NOT NULL,
    order_date TIMESTAMP,
    customer_id TEXT NOT NULL REFERENCES customer,
    total_amount NUMERIC
);

CREATE TABLE line_item (
    id TEXT PRIMARY KEY,
    order_id TEXT NOT NULL REFERENCES sales_order,
    description TEXT NOT NULL,
    line_total NUMERIC NOT NULL
);

INSERT INTO customer VALUES
    ('C1', 'John Doe'),
    ('C2', 'Juan Dela Cruz');

INSERT INTO sales_order VALUES
    ('O1', '001', '1996-07-08 00:00:00.0', 'C2', 123.45),
    ('O2', '002', NULL, 'C1', 5000);
