Minimum number of attributes in a primary key?

Question

If the degree of an entity is 8, what is minimum number of attributes required to form the primary key?

Answer 1

See this definition of "degree of an entity relationship". Is that what you are talking about? If so it would have no bearing on the number of attributes in the primary key, which could be anything from 1 up.

Answer 2

"which could be anything from 1 up."

Another one who never heard of empty keys, I guess.

The relational model allows the definition of keys that have no attribute whatsoever. It is the equivalent of a database constraint to the effect that the concerned relvar ("table") can hold only one row.

So the correct answer, from the perspective of the relational model, is : "zero".