Add support for cost centers

Agreed, it's not necessarily a "core" book keeping feature. Another thing to add would be Project accounting (http://en.wikipedia.org/wiki/Project_accounting) which is useful for campaigns etc, but isn't really core either.

I've attached a patch containing a few changes to Ledger Account Entry module that were necessary due to #1514940: Fieldable Account Entries. It adds Ledger Cost Center integration to the ledger module. The changes should not be commited as is, because it's basically just a hack at the moment. We need to do it the proper way. Obviously the table for example needs to be solved more elegantly.

@m.stenta do you have ideas on how you'd like to see this solved?

Well, I agree that it might feel a bit too much to add yet another entity to Ledger, but it really isn't an account, and even though it would be somewhat possible to use that entity type for the purpose it would create poor structure (maybe not database wise but logically/information-wise). Cost centers are not equal to accounts, so even though they behave similarly, they are used differently. They point of them is to be able to track costs, for example to differentiate between sales/costs from two different stores within the same company.

In our current client scenario they have around 10 cost centers, one for each region in the country. They only need around 10 accounts so that would *only* be 100 accounts if we were to use your method. However, the only reason they have so few accounts is because they are not using Drupal for all of their accounting - only for membership fees. The traditional Swedish BAS account plan consists of ~100 accounts. Some organizations have 50+ cost centers.

I'm not sure I follow as to how it would be useful to have it on account level. That would bind the account to a cost center wouldn't it? And what I mentioned earlier would still apply (and become an issue). If you have 100+ accounts (not uncommon), and say, 50 stores. You'd then need 5000 accounts. Sure, that's very granular, but it's granular in the wrong way. It would also require that you add another account for each existing account if you add a new cost center. Cost centers belong to another dimension than accounts.

Or did I misunderstand you completely? :)

How do you foresee using this data in day-to-day Ledger use, or reporting?

We're using it to group account balances per cost center. Basically it's in a way like being able to look at all the numbers going in and out of a company - but divided into the company's sections (be it stores, sales channels, sales divisions etc.). One example would be to differentiate sales coming from e-commerce from sales coming from a physical store. Using cost centers you can look at any book-keeping report (balance sheet, income statement), but filter on a specific cost center. You can, for example, single out a single store in a chain of stores and see how that particular store is doing.

By having the reference on the Account level, instead of on the Account Entry level, you only have to enter the "Cost Center" once (during setup of accounts) instead of EVERY time you are entering a transaction. The fact that an account is assigned to a cost center will therefore imply that any account entries made to that account are from that Cost Center.

I was originally thinking that it could be enough to have the reference on the transaction rather than on each account entry but I've taken a look att two different book-keeping systems and they both keep the reference on the account entry level. It's also way more future proof, and useful for the occasions where you actually have multiple cost centers being affected on a single transaction.

Closing since #1514940: Fieldable Account Entries will handle the ability for Ledger Cost Center to integrate properly with the ledger module.