Lecture 3

Question 1

1NF (first normal form)

Answer 1

First normal form says that all column values must be atomic.

At the intersection of each row and each Colin there must be only 1 value

Question 2

2nd normal form

Answer 2

A table is said to be in the second normal form,if it is in 1NF and every non-key column is fully dependent on the (entire) primary key.

Question 3

3NF (third normal form)

Answer 3

A table is in 3 normal form if it is 2NF and has no transitive dependencies (1 non key field depending on another non-key field)

Question 4

Foreign key

Answer 4

It is a key that is used to link two tables. A foreign key must first exist as a primary key in another table before it can become the foreign key.

Question 5

Primary key

Answer 5

Is used to uniquely identify a record in a table

Question 6

A composite primary key

Answer 6

Is a primary key with multiple fields

Question 7

Cardinality

Answer 7

How many entities of A must exist for 1 instance of entity B