7
5
Concepts of Database Management, 4
th
Edition, Pratt & Adamski
Keys
•
Column(s) C is primary key for table T if:
•
Property 1
: All columns in T are functionally dependent on C
•
Property 2
: No subcollection of columns in C (assuming C is
a collection of columns and not just a single column) also
has Property 1
Is class a primary key?