how to create table in wordpress database

function myplugin_update_db_check() {
    global $jal_db_version;
    if ( get_site_option( 'jal_db_version' ) != $jal_db_version ) {
        jal_install();
    }
}
add_action( 'plugins_loaded', 'myplugin_update_db_check' );