i****a
发帖数: 36252 | 1 TableA
Col_PK
TableB
Col_PK
Col_FK -> TableA.Col_PK
TableC
Col_FK -> TableB.Col_PK (this is necessary)
Col_FK2 -> TableA.Col_PK (this is optional. should I create this FK?) |
B*****g
发帖数: 34098 | 2 FK的作用是啥？
【在 i****a 的大作中提到】
: TableA
: Col_PK
: TableB
: Col_PK
: Col_FK -> TableA.Col_PK
: TableC
: Col_FK -> TableB.Col_PK (this is necessary)
: Col_FK2 -> TableA.Col_PK (this is optional. should I create this FK?)
|
i****a
发帖数: 36252 | 3 if I create the extra FK, can reduce a table join when i only need results
from TableA and TableC, and that's the most frequently used join. Is there
any design principle against doing that?
【在 B*****g 的大作中提到】
: FK的作用是啥？
|
B*****g
发帖数: 34098 | 4 没听说过FK有这好处，有link吗？
【在 i****a 的大作中提到】
: if I create the extra FK, can reduce a table join when i only need results
: from TableA and TableC, and that's the most frequently used join. Is there
: any design principle against doing that?
|
a**4
发帖数: 1050 | |
i****a
发帖数: 36252 | 6 我还是老老实实 follow normalization 吧
【在 B*****g 的大作中提到】
: 没听说过FK有这好处，有link吗？
|
