...can be accomplished by basic relational algebra operations?
Explain how the division operation can be accomplished by basic relational algebra operations?相关知识点: 试题来源: 解析 除法操作可以通过投影(Projection)、笛卡尔积(Cartesian Product)、差集(Set Difference)实现。具体步骤为:首先用投影和笛卡尔积生成所有可能的组合,再用差集筛选出符合条件的元组,最终通过投影...