什么是亲子关系？ [英] What are Parent-Child relationships?

问题描述

在我的情况下，我有一个部分（Say螺丝）和产品资料。为了论证，产品材料（如钢铁）只能属于一个部分（但不在现实世界中）。所以这是1：n。该部分将在ProductMaterial表中将其作为fk的pk。

在这种情况下，哪个是父母，哪个是小孩？

解决方案

您可以通过这种方式解释数据库中的1：n关系：一个小孩永远是保存外键的模型，因为这表示它所属的位置。

当然，如果你有自己的引用模型/表，你必须用不同的方式来看它。

What is the parent and what is the child in a sql relationship?

In my case, I have a part (Say screw), and product material. For argument's sake, a product material (eg steel) can only belong to one part (but not in the real world). So this is 1:n. The part will have its pk as a fk in the ProductMaterial table.

Which is parent and which is child in this case?

解决方案

You can interpret a 1:n relationship in database this way: A child is always that model which holds the foreign key as this indicates where it belongs to.
Of course if you have self referencing models/tables you have to look at it in a different way.

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