Creating new table vs adding new field

Question

I am having following data :

Fabric Cost

time     |   No fabric|BangloreSilk|Chanderi|.... <- fabric types
--------------------------------------------
01/15    |         40 |         25 |...
02/15    |         45 |         30 |...
.....    |        ... |        ... |...

Dyeing Cost

time     |   No fabric|BangloreSilk|Chanderi|.... <- fabric types
--------------------------------------------
01/15    |         40 |         25 |...
02/15    |         45 |         30 |...
.....    |        ... |        ... |...

And here list of fabric types will be same for both the data.
Now to add this data I created following tables :

fabric_type

id                  int
fabric_type_name    varchar

And then I have two approaches .

Approach 1 :

fabric_cost

id                  int
fabric_type_id      int (foreign key to fabric_type)
cost                int

deying_cost

id                  int
fabric_type_id      int (foreign key to fabric_type)
cost                int

Approach 2 :

fabric_overall_cost

id                  int
fabric_type_id      int (foreign key to fabric_type)
cost                int
fabric_or_dyeing    bit (to represent 0 for fabric cost and 1 for dyeing cost)

Now the question is which approach will be better??

Answer 1

Maybe you can create another table - cost_subjects

cost_subjects

id                  byte
subject             varchar

costs

id                  int
fabric_type_id      int (foreign key to fabric_type)
cost                int
cost_subject        byte (foreign key to cost_subjects table)

And then you can extend the table with more subjects to include in costs of fabric

Answer 2

It really depends on your requirements. Are there other columns that are unique only for the fabric_cost table? Are there other columns that are unique only for the dyeing_cost table? Meaning will your 2 tables grow independently? If yes, approach 1 is better. Otherwise, approach 2 is better because you won't need to do CRUD on 2 separate tables (for easier maintenance). Another approach would be:

id                  int
fabric_type_id      int (foreign key to fabric_type)
fabric_cost         float/double/decimal
dyeing_cost         float/double/decimal

This third approach is if you always have both costs. You might not want to use int for cost. Again, it depends on your requirements.