Normalization: A Workshop for Everybody Pt. 2

Postgresql East - 2010

Philadelphia, PA

Databases – A Historical Perspective

Part Two

Why be normal?


•The Normal Forms

• Normalization Workshop


Normal Forms

The truth,The whole truth,

And nothing but the truth.


First Normal Form (1NF) sets the very basic rules for an

organized database:1. Eliminate duplicative columns

from the same table.2. Create separate tables for each group of related data and identify each row with a unique column

(the primary key).


Second Normal Form 2NF: 1. Remove subsets of data

that apply to multiple rows of a table and place them in

separate tables. 2. Create relationships

between these new tables and their predecessors

through the use of foreign keys.


Third Normal Form:

1. Meet the requirements of both 1NF and 2NF

2. Remove columns that are not fully dependent upon the

primary key.


http://databases.about.com/od/specificproducts/l/aa1nf.htm

http://databases.about.com/od/specificproducts/a/2nf.htm

http://databases.about.com/library/glossary/bldef-column.htm

http://databases.about.com/library/glossary/bldef-primarykey.htm

4th and 5th Normal Form –

These are data purity abstractions which are not

routinely used in production databases.


6th Normal Form –

Found only in alien databases.


"The key, the whole key, and nothing but the key, so help me

Codd."


And, a note about data

warehousing…

De-normalization is a key tenet of data warehousing.


BRAINSTORM!!!


Questions?Comments?


EndOf

PartTwo


Normalization: A Workshop for Everybody Pt. 2

Documents

Transcript of Normalization: A Workshop for Everybody Pt. 2