Should my fact table be normalized?

Hexxx

This is the fact table.
The PK are time_id and station_id as they both are needed to know the values of the remaining columns.

I am also doing a customizable search where users would be able to see what they can select, for example, some may want to see all, whereas some users may only want to see the columns dealing with viewership.

The problem I am having is should I break down the fact table into smaller groups, such as viewership, male, female, etc where the same PK (time_id and station_id) would be present in all the groups and would be used to get their values.

There would always be values (even if they are 0) once a key exists but I don't know if I should break the fact table into more manageable pieces.

+---------+------------+-------------------------+--------------------------+-------------------------+------------------+-------------------+-------------------+--------------------+-------------------+------------+-------------+---------------------+----------------------+---------------------+--------------+---------------+------------------------+-------------------------+------------------------+-----------------+------------------+-----------------------+------------------------+-----------------------+----------------+-----------------+-----------------------+------------------------+-----------------------+----------------+-----------------+-----------------------+------------------------+-----------------------+----------------+-----------------+-----------------------+------------------------+-----------------------+----------------+-----------------+-----------------------+------------------------+-----------------------+----------------+-----------------+-----------------------+------------------------+-----------------------+----------------+-----------------+-----------------------+------------------------+-----------------------+----------------+-----------------+-----------------------+------------------------+-----------------------+----------------+-----------------+-----------------------+------------------------+-----------------------+----------------+-----------------+-----------------------+------------------------+-----------------------+----------------+-----------------+-----------------------+------------------------+-----------------------+----------------+-----------------+-----------------------+------------------------+-----------------------+----------------+-----------------+-----------------------+------------------------+-----------------------+----------------+-----------------+-----------------------+------------------------+-----------------------+----------------+-----------------+-----------------------+------------------------+-----------------------+----------------+-----------------+-----------------------+------------------------+-----------------------+----------------+-----------------+-------------------------+--------------------------+-------------------------+------------------+-------------------+-------------------------+--------------------------+-------------------------+------------------+-------------------+-------------------------+--------------------------+-------------------------+------------------+-------------------+-------------------------+--------------------------+-------------------------+------------------+-------------------+-------------------------+--------------------------+-------------------------+------------------+-------------------+-------------------------+--------------------------+-------------------------+------------------+-------------------+-------------------------+--------------------------+-------------------------+------------------+-------------------+
| time_id | station_id | viewership_nos_captured | viewership_nos_available | viewership_nos_possible | viewership_share | viewership_rating | male_nos_captured | male_nos_available | male_nos_possible | male_share | male_rating | female_nos_captured | female_nos_available | female_nos_possible | female_share | female_rating | household_nos_captured | household_nos_available | household_nos_possible | household_share | household_rating | age_gr0__nos_captured | age_gr0__nos_available | age_gr0__nos_possible | age_gr0__share | age_gr0__rating | age_gr1__nos_captured | age_gr1__nos_available | age_gr1__nos_possible | age_gr1__share | age_gr1__rating | age_gr2__nos_captured | age_gr2__nos_available | age_gr2__nos_possible | age_gr2__share | age_gr2__rating | age_gr3__nos_captured | age_gr3__nos_available | age_gr3__nos_possible | age_gr3__share | age_gr3__rating | age_gr4__nos_captured | age_gr4__nos_available | age_gr4__nos_possible | age_gr4__share | age_gr4__rating | age_gr5__nos_captured | age_gr5__nos_available | age_gr5__nos_possible | age_gr5__share | age_gr5__rating | age_gr6__nos_captured | age_gr6__nos_available | age_gr6__nos_possible | age_gr6__share | age_gr6__rating | age_gr7__nos_captured | age_gr7__nos_available | age_gr7__nos_possible | age_gr7__share | age_gr7__rating | edu_gr0__nos_captured | edu_gr0__nos_available | edu_gr0__nos_possible | edu_gr0__share | edu_gr0__rating | edu_gr1__nos_captured | edu_gr1__nos_available | edu_gr1__nos_possible | edu_gr1__share | edu_gr1__rating | edu_gr2__nos_captured | edu_gr2__nos_available | edu_gr2__nos_possible | edu_gr2__share | edu_gr2__rating | edu_gr3__nos_captured | edu_gr3__nos_available | edu_gr3__nos_possible | edu_gr3__share | edu_gr3__rating | edu_gr4__nos_captured | edu_gr4__nos_available | edu_gr4__nos_possible | edu_gr4__share | edu_gr4__rating | edu_gr5__nos_captured | edu_gr5__nos_available | edu_gr5__nos_possible | edu_gr5__share | edu_gr5__rating | edu_gr6__nos_captured | edu_gr6__nos_available | edu_gr6__nos_possible | edu_gr6__share | edu_gr6__rating | edu_gr7__nos_captured | edu_gr7__nos_available | edu_gr7__nos_possible | edu_gr7__share | edu_gr7__rating | occup_gr0__nos_captured | occup_gr0__nos_available | occup_gr0__nos_possible | occup_gr0__share | occup_gr0__rating | occup_gr1__nos_captured | occup_gr1__nos_available | occup_gr1__nos_possible | occup_gr1__share | occup_gr1__rating | occup_gr2__nos_captured | occup_gr2__nos_available | occup_gr2__nos_possible | occup_gr2__share | occup_gr2__rating | occup_gr3__nos_captured | occup_gr3__nos_available | occup_gr3__nos_possible | occup_gr3__share | occup_gr3__rating | occup_gr4__nos_captured | occup_gr4__nos_available | occup_gr4__nos_possible | occup_gr4__share | occup_gr4__rating | occup_gr5__nos_captured | occup_gr5__nos_available | occup_gr5__nos_possible | occup_gr5__share | occup_gr5__rating | occup_gr6__nos_captured | occup_gr6__nos_available | occup_gr6__nos_possible | occup_gr6__share | occup_gr6__rating |
+---------+------------+-------------------------+--------------------------+-------------------------+------------------+-------------------+-------------------+--------------------+-------------------+------------+-------------+---------------------+----------------------+---------------------+--------------+---------------+------------------------+-------------------------+------------------------+-----------------+------------------+-----------------------+------------------------+-----------------------+----------------+-----------------+-----------------------+------------------------+-----------------------+----------------+-----------------+-----------------------+------------------------+-----------------------+----------------+-----------------+-----------------------+------------------------+-----------------------+----------------+-----------------+-----------------------+------------------------+-----------------------+----------------+-----------------+-----------------------+------------------------+-----------------------+----------------+-----------------+-----------------------+------------------------+-----------------------+----------------+-----------------+-----------------------+------------------------+-----------------------+----------------+-----------------+-----------------------+------------------------+-----------------------+----------------+-----------------+-----------------------+------------------------+-----------------------+----------------+-----------------+-----------------------+------------------------+-----------------------+----------------+-----------------+-----------------------+------------------------+-----------------------+----------------+-----------------+-----------------------+------------------------+-----------------------+----------------+-----------------+-----------------------+------------------------+-----------------------+----------------+-----------------+-----------------------+------------------------+-----------------------+----------------+-----------------+-----------------------+------------------------+-----------------------+----------------+-----------------+-------------------------+--------------------------+-------------------------+------------------+-------------------+-------------------------+--------------------------+-------------------------+------------------+-------------------+-------------------------+--------------------------+-------------------------+------------------+-------------------+-------------------------+--------------------------+-------------------------+------------------+-------------------+-------------------------+--------------------------+-------------------------+------------------+-------------------+-------------------------+--------------------------+-------------------------+------------------+-------------------+-------------------------+--------------------------+-------------------------+------------------+-------------------+

continued below...

Hexxx

The main grouping would be
1. Viewership
2. Male
3. Female
4. Household
5-12. Age groups (8 groups: 0 to 7)
13-20. Education groups (8 groups: 0 to 7)
21-27. Occupation groups (7 groups: 0 to 6)

Each of these would then be a tables, giving 27 fact tables: with time_id and station_id as the key, and five other columns (nos_possible, captured, available, shares and rating) which are their numbers.

Piranha

You should not break it down to 27 tables. But you should break it down to 2 or 3 tables. Like this:

table groups
id int primary key
groupname varchar // ie viewship, male, household

table answers
time_id // this and next 2 PK
station_id  // this, next and previous PK
groups_id int // this and previous 2 PK FK to groups
nos_possible
captured
available
shares
rating

Then you get all you need in a very simple way. If you want you can add a table with only time_id and station_id and make those rows to FK in answers.

I personally would use autoincremented values to the PK, but that is a matter of choise rather than what is "right" and "wrong". Just make sure that there is no way that the time_id and station_id can be changed in the future and it is ok with those as PK.