ON DELETE RESTRICTON DELETE CASCADEpublic.customersTABLEiduuidPKemailtextUQNNcreated_attimestamptzNNpublic.ordersTABLEiduuidPKcustomer_iduuidFKNNstatustextNNtotalnumeric(12,2)public.order_itemsTABLEiduuidPKorder_iduuidFKNNskutextNNquantityintNN订单数据库结构三张物理表,含 SQL 类型、约束标签和列级外键。与 ER 图不同,外键线在列与列之间锚定,并标注引用动作。唯一的级联删除用强调色绘制,被级联的表表头带底色。在编辑器中打开