Databases

[phorce]

Hello there, wonder if you can help me..

I've got to normalise a database, up to 3NF and wonder if you do the normalisation on each individual table, OR the database as a whole?

I've got this so far:

Attributes:
registration_No
Make
Model
Type
Cylinder
Body Type
Transmission
Air Conditioning
Colour
Photo
passenger

The key is registration_No and the functional dependancies are:
registration_No -> {Make, Model, Type, Cylinder, Body Type, Transmittion, Air_Conditioning, Color, Photo, Passenger}

And this table is in: 1NF, 2NF and 3NF..

Does this look ok, or am I doing it wrong?

Thanks :)

[sufyan2011]

Well, according to my experience, I don't remember exactly the NFs, but the suggestion for table design is as follow: (Sorry if you already did it)

1 - All attributes other than registration_No should be constant values, there should be orphan tables for these tables e.g. Color should have table like as follow:

Color ID - Auto Increment
Color - the name of color e.g. green, red, yellow
Color Code - e.g. GR, YL, RD

and in your main table instant of hard code color, color code from this table should go to DB. I think this is 2nd or 3rd NF. Simlarl for all other attributes you think that it should be like that.

[sufyan2011]

Besides, As far I know NFs are on table level, e,g, remove reduncy, removed dynamic values columns (e.g. instant of total amount, you should make two column Unit price and Number of items), make orphan tables for constant etc.

[phorce]

Hey thanks for the reply, this is really confusing me :(

I have like 7 tables in this database.. If I was to create a separate table for like Colour etc, I'd have like a hundred tables aha!

[sufyan2011]

You have just 7 tables, make table for only those attributes you think necessary for. other option is XML file.

[Netcode]

You normalize a database and not the table. Since normalization affects tables which are primary components of a database, then normalization is said to be carried out on the database which basically involves breaking down table structure to avoid redundancy.

What you have so far is just one table with its columns listed, maybe giving us a general overview of what your database is about would help better.

[Webmastergrace]

may i know the type of normalization (1nf, 2nf and many more ) what they described?
how they are beneficial for database?

[Webmastergrace]

let me know some new(updated ) topics related to data base accessibility . if some tell me some kind of help then it is very helpfull