CREATE TABLE IF NOT EXISTS suppliers (
    id INT AUTO_INCREMENT PRIMARY KEY,
    name_en VARCHAR(255) NOT NULL,
    name_ar VARCHAR(255) NOT NULL,
    contact_person VARCHAR(255),
    phone VARCHAR(50),
    email VARCHAR(100),
    address TEXT,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);

ALTER TABLE drugs ADD COLUMN expiry_date DATE DEFAULT NULL;
ALTER TABLE drugs ADD COLUMN supplier_id INT DEFAULT NULL;
ALTER TABLE drugs ADD CONSTRAINT fk_drugs_supplier FOREIGN KEY (supplier_id) REFERENCES suppliers(id) ON DELETE SET NULL;