CREATE TABLE asset_files (
    id INT AUTO_INCREMENT PRIMARY KEY,
    asset_id INT NOT NULL,
    filename VARCHAR(255) NOT NULL,
    original_filename VARCHAR(255) NOT NULL,
    path VARCHAR(500) NOT NULL,
    mime VARCHAR(100) NOT NULL,
    size INT NOT NULL,
    uploaded_by INT,
    uploaded_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    FOREIGN KEY (asset_id) REFERENCES assets(id) ON DELETE CASCADE,
    FOREIGN KEY (uploaded_by) REFERENCES users(id) ON DELETE SET NULL,
    INDEX idx_asset_id (asset_id),
    INDEX idx_uploaded_by (uploaded_by),
    INDEX idx_uploaded_at (uploaded_at)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;