Class 05 Flashcards
normalization
1
Q
what are database anomalies?
A
insertion + deletion + modification anomaly
2
Q
what is an insertion anomaly?
A
inconsistent data
3
Q
what is a deletion anomaly?
A
incomplete data
4
Q
what is a modification anomaly?
A
when too many rows are impacted
5
Q
what is the first normal form?
A
multivalued values get separate rows
6
Q
what is the second normal form?
A
partial functional dependencies are removed + duplicated data get a separated table
7
Q
what is functional dependency?
A
a constraint between 2 attributes (ie. SSN)
8
Q
what is the third normal form?
A
transitive dependencies are removed
9
Q
what are the steps to creating a table?
A
- begin with entities
- map the core attributes
- inspect relationship sets
