Lernkarten
3 Exakte Antworten
16 Text Antworten
2 Multiple Choice Antworten
Rationale Algebra:
\(\sigma\) entrpicht welcher operation( in englisch)
select operation
Rationale Algebra:
\(\Pi \) entrpicht welcher operation( in englisch)
project operation
Duplicated rows are removed from the result!!! since relations are sets
composition of relations
{(1,2)}.{(2,3)} = ?
{(1,3)}
Rationale Algebra:
"v" entrpicht welcher operation( in englisch)
union operation
set difference operator: difference of set r and s:
r-s
must have same arity (same type size), the attributes must match
What ist the notation of cardinality of A
|A|
What is an unordered collection of ojects, which are all different?
a set
\(A \cup B\) means
A union B
A difference B
A intersection of B
A complement B
