An Alternate DB Model

I'm experimenting with a new data model, inspired by ledger-cli and datamapper single table inheritance.

Take a look:

# Xact = transaction
class Xact
  include DataMapper::Resource

  property :id,Serial
  property :posted_on,Integer
  property :memorandum,String
  has n, :assets
  has n, :liabilities
  has n, :equities
  has n, :expenses
  has n, :revenues
  has n, :banks

end


# Postings are the individual account changes
class Posting
  include DataMapper::Resource

  property :id,Serial
  property :type,Discriminator
  property :xact_id,Integer
  property :commodity,String
  property :quantity,BigDecimal, :scale => 2, :precision => 5

  belongs_to :xact
end

# Single table inheritance for every account
class Asset < Posting; end
class Liability < Posting; end
class Equity < Posting; end
class Revenue < Posting; end
class Expense < Posting; end
class Bank < Asset; end

The idea here is that each account is an object. The code above has the account types and then a bank account. This is obviously pre-alpha code, but the idea is there.

Its a big departure away from the way I've traditionally modeled accounting databases, so why bother?

I like this model because its super simple, and because it leverages some quality work that's already been done with datamapper, and it supports the sort of quick, instant reporting that is core to ledger-cli, especially the balance feature.

I'm interested in aligning Regdel with ledger to add to the traction its established. Open source accounting and bookkeeping software could use a little unity in my humble opinion. For awhile I felt that the single plain text file was a serious limitation, but those limitations might be alleviated with the combination of a SQLite and git, but that's a topic for another day.

Feedback about this new data model is much appreciated!