Normal Function

definition

column

Simply a single vertical representation of data storage in database table

functional dependency

Once providing some columns A, the other columns B are implied. This is said to be B functionally depends on A, or A -> B

key column

The column that comprises key

key

A set of columns that is minimum, and is able to determine the rest of columns in table

partial functional dependency

Part of the key its own is able to determine some columns

full functional dependency

Only the key itself is able to determine some columns, no partial functional dependency available

transitive functional dependency

some columns A functionally depend on another columns B, which by its own depends on one another columns C.
All the columns mentioned here not necessarily be key or key column at all.

normal function

1NF

Ensure every column is atomic

2NF

Ensure key columns have full functional dependency to non-key columns.
Note that partial dependency between non-key columns is fine

3NF

Ensure no transitive functional dependency between non-key column.
This means transitive dependency between key column is fine

BCNF

Ensure no transitive functional dependency between key column