I have a database which contains a table BUILDING with in each row details about some building, another table BUILDING_UNIT contains rows with details about a single building unit which refers with a foreign key to the belonging BUILDING.ID. The BUILDING_UNIT table also refers to a table CATEGORY which tells whether the BUILDING_UNIT is of category A,B,C,D again with a foreign key pointing to CATEGORY.ID.
Now the final cost of renting the building unit depends on its building, category and on the number of days it is rented and specific period of the year. We only rent them weekly so I might as well use weeks only however I'd like it to be as flexible as possible in the future.
I cannot convince myself on a table which can represent this situation.
Do I have to use a table with coefficients for each day of the year and then a table with coefficients for A,B,C,D and then a table with coefficients for each Building and then somehow calculate a result?
Is there some standard and recognized implementation for problems of this type?
EDIT: Notice the solution should abstract from the formula for calculating the cost which might change in the future. However I might be asked to make a specific week of the year, for building unit X inside building Y to cost 300$ while the week after 600$. Generally building units inside the same building and in the same week cost the same, however that might change in future so I'd like to treat already all specific cases.