Chapter 13 Flashcards
1
Q
In algorithm, graph problem called what
A
Isomorphism problem
2
Q
What is paradox
A
Trying to make information accessible using tables resulted in an inability to query them
3
Q
ER (Entity relationship) vs DM (Dimensional modelling)
A
ER is for OLTP and DM is for DSS query performance. ER is for micro and DM is for macro purpose.
4
Q
What are two methods to simplify ER data model
A
- De-normalization
- Dimensional modelling
5
Q
What are 2 types of tables in dimensional modelling
A
- Fact table
- Dimensional table
6
Q
What is fact table
A
It is main table. It has primary key that consist of multiple columns.
7
Q
Does fact and dimensional table single line
A
Yes
8
Q
What are 2 schema in DM
A
- Star schema
- Snow-flake schema
9
Q
What schema is used in OLTP environment
A
Snow-flake schema
10
Q
What schema is used in DSS environment
A
Star schema
