CREATE TABLE IF NOT EXISTS `client_contracts` (
    `id` INT AUTO_INCREMENT PRIMARY KEY,
    `client_id` INT NOT NULL,
    `contract_id` INT NOT NULL,
    `signature_data` TEXT NOT NULL,
    `signed_at` TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    FOREIGN KEY (`client_id`) REFERENCES `clients`(`id`) ON DELETE CASCADE,
    FOREIGN KEY (`contract_id`) REFERENCES `contracts`(`id`) ON DELETE CASCADE
);