CREATE TABLE IF NOT EXISTS customers (
    id SERIAL PRIMARY KEY,
    name TEXT NOT NULL,
    email TEXT,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);

CREATE TABLE IF NOT EXISTS licenses (
    id SERIAL PRIMARY KEY,
    license_key TEXT UNIQUE NOT NULL,
    customer_id INTEGER REFERENCES customers(id),
    license_type TEXT NOT NULL,
    valid_from DATE NOT NULL,
    valid_until DATE NOT NULL,
    is_active BOOLEAN DEFAULT TRUE
);