开发者

non Identified relationship and foreign keys

开发者 https://www.devze.com 2023-03-03 18:32 出处:网络
if i have two non identif开发者_运维问答ied relationships, FK_one and FK_two. The only way, that i cant put them as a single primary key is when i add PK to the FK_one and FK_two, but if i do that, th

if i have two non identif开发者_运维问答ied relationships, FK_one and FK_two. The only way, that i cant put them as a single primary key is when i add PK to the FK_one and FK_two, but if i do that, the relation is now an identified.

So my question is: i can only have two foreign keys as a PK if they are an Identified relationship, correct? otherwise they can't be used as PK even if I have two or more FK (non Identified relationships)


An identified relationship is "identified" with 2 or more FKs as primary keys and without a surrogate key. So you end up with a composed primary key, but as far as I know you can have all the primary keys you want but that's not good for the server performance.

0

精彩评论

暂无评论...
验证码 换一张
取 消