如何参照希斯定理分解表格? [家庭作业]

发布于 2024-12-15 20:29:51 字数 614 浏览 6 评论 0原文

我对希斯定理有一个大致的了解,但我很难解决这个问题:

Use the functional dependencies to carry out a non-loss decomposition in line with Heath’s Theorem,
to produce a set of tables in 3NF (3 rd Normal Form).

Say why each decomposed table is in 3NF and no longer just 2NF

假设我有以下 FD:

{orderId} -> {employeeId, unitPrice}

这是否意味着我得到正在分解的表(父级),使用 SQL 将其转换为多个表(分解) )。从上面的结果将包括一个包含以下字段的表:

orderId, employeeId and unitPrice

为了解释 3NF 与 2NF,我是否只需确认新表中不再有任何传递依赖项。这是我对3NF要求的理解。

我如何解释上述所有与希斯定理相关的内容?

I have a general understanding of Heath Theorem but I'm having trouble getting my head around this question:

Use the functional dependencies to carry out a non-loss decomposition in line with Heath’s Theorem,
to produce a set of tables in 3NF (3 rd Normal Form).

Say why each decomposed table is in 3NF and no longer just 2NF

Say I have the following FD:

{orderId} -> {employeeId, unitPrice}

Does this mean I get the table being decomposed (parent) use SQL to convert it to multiple tables (decomposed). From the above the result would include a table with the fields:

orderId, employeeId and unitPrice

To explain 3NF vs 2NF do I just confirm there are no longer any transitive dependencies in the new table. This is my understanding of the 3NF requirement.

How do I go about explaining all of the above with relation to Heath's Theorem ?

如果你对这篇内容有疑问,欢迎到本站社区发帖提问 参与讨论,获取更多帮助,或者扫码二维码加入 Web 技术交流群。

扫码二维码加入Web技术交流群

发布评论

需要 登录 才能够评论, 你可以免费 注册 一个本站的账号。
列表为空,暂无数据
我们使用 Cookies 和其他技术来定制您的体验包括您的登录状态等。通过阅读我们的 隐私政策 了解更多相关信息。 单击 接受 或继续使用网站,即表示您同意使用 Cookies 和您的相关数据。
原文