Professor Week 5

Question 1

Normalization

Answer 1

Decomposing relations to avoid anomalies when inserting, updating or deleting data.

Question 2

Anomalies in Data

Answer 2

Redundancy, Update, Delete, Insert

Question 3

What is functional dependency?

Answer 3

When one value determines another value and only determines one value.

EmployeeID -> name
EmployeeID -> dept. name
emp_ID -> salary

OR empID -> name, dept_name. salary

Determinant -> employeeID

Question 4

What is a candidate key?

Answer 4

Determinant that determines the rest of the values.

Question 5

Second Normal Form

Answer 5

In 1NF and…
all of its non-key attributes are dependent on all of the key

OR

the primary key consists of only of one attribute

OR

No non-key attributes exist in the relation (all of the attributes are part of the key)

Question 6

Non-key attributes

Answer 6

all attributes that are not part of the primary key

Question 7

Dependent

Answer 7

Attributes appear on the right side of a function dependency

Question 8

Partial dependencies

Answer 8

A(1,2,3,4) 1 and 2 are primary key
fds:
1,2 -> 3,4 is a full dependency
1 ->3 is a partial dependency and breaks 2NF

Question 9

Third Normal Form

Answer 9

If it is in 2NF and is free of transitive dependency

Question 10

Transitive Dependency Format

Answer 10

Attribute A -> Attribute B -> Attribute C

A is typically primary key
B and C are non-key attributes

Violation: when a non key attr is determining another non-key attr