2 ms·

What if it can be 0 or 1 set each? So null several columns, perhaps constrain they can only be null (resp. not null) together, ... Or just have a single nullab

by OJFord 4y ago

What if it can be 0 or 1 set each? So null several columns, perhaps constrain they can only be null (resp. not null) together, ... Or just have a single nullable fk to a table where the data's not nullable.

bazoom42 4y ago
If multiple columns can only be null/non-null together it indicates a dependency which should be normalized.
- OJFord 4y ago
  Yes, but I was replying to 'no such thing as 1:1 relationships, just put it in the same table'.
  - bazoom42 4y ago
    But you are talking about 1:0..1 which is different from plain 1:1 relationships.
deleted 4y ago
[deleted]
Akronymus 4y ago
As much as I dislike nullable fields, I personally think that the alternative to having them (Making any nullable instead a table) can make working with it too cumbersome. > Or just have a single nullable fk to a table where the data's not nullable. Why not the other table having a non-nullable pk/fk to the main table?
- OJFord 4y ago
  Yes or that, didn't mean to preclude that, just that 'somehow linked' table is better than bunging it all in main one IMO.