simple key → 1 field

domain key → natural key

natural key → no need for artificial column

primary key →

candidate key → minimal superkey = { primary key ∪ alternate key }

trivial super key → all columns

super key = { candidate key ∪ compound key } = fields that uniquely identify a row

surrogate key

composite key = { compound key ∪ a₁ ∉ super key }

Tuple → row

Attribute → field

Relation → table

f(0) = 1
f(1) = 2
f(2) = 4
f(3) = 8
f(4) = 16
f(5) = 32
f(6) = 64
f(7) = 128

|P| = 2ⁿ cardinality of power set

power set → every possible combination of fields
super key →
candidate key →
primary key