Title: Information Systems for Engineers / Topic 4

Closure

Q: What must uphold for a union of two relations?
A: 1. Same Attributes
2. Same Domains
3. Same Order (if relation is defined mathematicaly)

Union

Intersection

Subtraction

Projection

Selection

Renaming

Cartesian Product

Natural Join

Theta Join

Q: What type of Aggregations are there?
A: - Count
- Sum
- Average
- Min
- Max
- Mode
- Variance