Franz.Rasper@izb.de schrieb:
>> Make the table:
>
>> id | year | value
>> ---+------+------
>> 1 | 1970 | 23
>> 1 | 1971 | 25
>> 1 | 1972 | 28
>> ...
>> 2 | 1972 | 5
>> 3 | 1971 | 94
>> 3 | 1972 | 102
>
>> primary key: (id,year)
>> value not null
>> and be ready.
>> the import/update reasons are pretty easily solved
>> that way too.
>
> then your primary key will consists of two fields.
> I prefer the primary keys with one field only.
Maybe but this would not help you with this situation here :-)
I think this fittes best but I'm open to alternative approaches.
The wide-table of the original design has definitively much more
problems. And if id is independent from year (not really month or
so) it is usefull imho to have a compound primary key.
Alternatively you can skip the primary key part and just define:
id not null,
year not null,
value not null
unique (id,year)
Regards
Tino