Relations Flashcards
1
Q
What is a “Relation”?
A
A table with columns and rows
2
Q
What is an attribute?
A
Named column of a relation
3
Q
What is a domain?
A
The Type of a column
4
Q
What is a tuple?
A
A row in a table; a tuple
5
Q
What is a relational database?
A
A collection of normalised relations
6
Q
What is the type of a table/relation?
A
Set([l1 : T1, …, ln : Tn])
7
Q
What is a superkey?
A
Any column or set of columns from a relation that uniquely identifies a record.
8
Q
What is a candidate key?
A
A key with the minimum possible number of attributes needed to uniquely identify a row.
So there are no superkey subsets of a candidate key.
9
Q
A
