proper format for this database table
John Salerno
johnjsal at NOSPAMgmail.com
Fri Oct 20 13:24:38 EDT 2006
Carsten Haese wrote:
>>> [id] [university] [yearStart] [yearEnd] [degreeEarned]
>>> 1 U of I 1971 1975 BS
>>> 1 U of I 1975 1976 MS
>>> 1 U of I 1976 1977 PhD
>>>
>> Thanks guys. I do plan to have an id entry for each person as well, I
>> just forgot to mention that. But since it's a primary key, I didn't know
>> I could list it more than once. Or does primary key not necessarily mean
>> unique?
>
> Primary key *does* mean unique in the table that defines it. However, if
> you take a primary key ID from one table and store it in a different
> table, that's a foreign key. There are no inherent uniqueness
> constraints on a foreign key.
>
So in the example above, isn't that using the same primary key multiple
times in the same table?
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