Entity-Relationship Model Flashcards
Define entity, relationship, connectivity, cardinality, chen notation, crow's foot notation
1
Q
What is considered as a SET of record?
A
entity/table
2
Q
What is the first stage of the design process?
A
conceptual modeling
3
Q
Notation modes used for DB data modeling
A
Chen Notation & Crow’s Foot
4
Q
Chen Style
A
- rectangle = entity
- oval = attribute
- diamond = relationship
Add * to the attribute you think is a key aka unique idenitifier
Use 0, 1, M to indicate entity relationship
5
Q
Crow’s Foot
A
- rectangle = entity
- entity name in top section
- attributes listed in bottom section
- mark keys as PK/FK when necessary
- Use ring (0), dash (1), crow’s foot (many)
6
Q
|| means . . .
A
one and only one
7
Q
0|
A
zero or one
8
Q
> |
A
one or more (looks like a Crow’s foot)
9
Q
> 0
A
zero, one, or more
