mod5- normalization

Question 1

Primarily a tool to validate and improve a logical
design so that it satisfies certain constraints that
avoid unnecessary duplication of data
The process of decomposing relations with
anomalies to produce smaller, well-structured
relations

Answer 1

data normalization

Question 2

A relation that contains minimal data redundancy and allows users to
insert, delete, and update rows without causing data inconsistencies

Answer 2

well-structured relations

Question 3

adding new rows forces the user to create duplicate
data

Answer 3

insertion anomaly

Question 4

deleting rows may cause a loss of data that would
be needed for other future rows

Answer 4

deletion anomaly

Question 5

changing data in a row forces changes to other
rows because of duplication

Answer 5

modification anomaly

Question 6

A table should not pertain to
more than one entity type.

Answer 6

true

Question 7

there are goals of normalization
1. Minimize data redundancy.
2. Simplify the enforcement of referential integrity constraints.
3. Make it easier to maintain data.
4. Provide a better design.

Answer 7

true

Question 8

why anomalies exist

Answer 8

Because there are two themes (entity types) in this one
relation. This results in data duplication and an unnecessary
dependency between the entities.

Question 9

The value of one attribute (the determinant)
determines the value of another attribute
Candidate Key:
A unique identifier. One of the candidate keys will become the primary
key
E.g., perhaps there is both a credit card number and SS# in a
table…in this case, both are candidate keys.
Each non-key field is functionally dependent on every candidate key

Answer 9

functional dependency

Question 10

No multivalued attributes
Every attribute value is atomic

Answer 10

first normal form

Question 11

1NF PLUS every non-key attribute is fully functionally
dependent on the ENTIRE primary key
Every non-key attribute must be defined by the entire
key, not by only part of the key
No partial functional dependencies

Answer 11

second normal form

Question 12

2NF PLUS no transitive dependencies (functional dependencies on nonprimary-key attributes)
Note: This is called transitive because the primary key is a determinant for
another attribute, which in turn is a determinant for a third
Solution: Non-key determinants with transitive dependencies go into a new
table; non-key determinant becomes primary key in the new table and stays as
a foreign key in the old table

Answer 12

third normal form