Pynomina/ledger


Wolfgang Fahl

Ledger Book[edit]

The pynomina Ledger Book model consists of four main classes:

  • Book
  • Account
  • Transaction
  • Split

These are the necessary classes which work together to represent a comprehensive financial ledger records.

Class Structure[edit]

0xfec2cab6.png

Book[edit]

The Book class represents the main container for all financial data. It includes:

  • Basic information: name, owner, creation date, and source URL
  • Collections of accounts and transactions
  • Methods for managing accounts and transactions, including:
    • get_stats(): Retrieves statistics about the book
    • filter(): Filters transactions by date range
    • create_account(): Creates a new account
    • add_account(): Adds an account to the book
    • lookup_account(): Finds an account by ID

Account[edit]

The Account class represents a hierarchy of individual financial accounts within the ledger. It includes:

  • account_id: Unique identifier for the account
  • name: Human-readable account name
  • account_type: Type of account (e.g., EXPENSE, INCOME)
  • description: Optional account description
  • currency: Account currency (default: EUR)
  • parent_account_id: Optional parent account for hierarchical structure

Transaction[edit]

The Transaction class represents individual financial transactions. It includes:

  • isodate: Date of the transaction in International Standards Organization date format yyyy-mm-dd
  • description: Description of the transaction
  • splits: List of Split objects representing the movement of money
  • payee: Optional payee information
  • memo: Optional additional notes
  • total_amount(): Method to calculate the total transaction amount

Split[edit]

The Split class represents the individual components of a transaction, showing how money moves between accounts. It includes:

  • amount: The amount of money involved in the split
  • account_id: The account associated with this part of the transaction
  • memo: Optional notes for this split
  • reconciled: Boolean indicating if the split has been reconciled

Example Data[edit]

Here's an example of how the ledger model is used in practice:

Yaml Format[edit]

owner: Wolfgang Fahl
url: https://github.com/WolfgangFahl/pynomina/blob/main/nomina_examples/expenses2024.yaml
since: 2024-10-06
accounts:
  Expenses:
    account_id: Expenses
    name: Expenses
    account_type: EXPENSE
    description: 'General Expenses'
    currency: EUR
  Expenses:Food:
    account_id: Expenses:Food
    name: Dining
    account_type: EXPENSE
    description: 'Expenses for Food'
    currency: EUR
    parent_account_id: Expenses
  Cash in wallet:
    account_id: Wallet
    name: Cash in Wallet
    account_type: EXPENSE
    description: ''
    currency: EUR
transactions:
  Bakery2024-10-06_0900_1:
    isodate: '2024-10-06'
    description: Bread
    splits:
      - amount: -3.50
        account_id: Cash in Wallet
      - amount: 3.50
        account_id: Expenses:Dining
        memo: Fresh sourdough bread
  Bakery2024-10-06_0900_2:
    isodate: '2024-10-06'
    description: Buns for Breakfast
    splits:
      - amount: -2.40
        account_id: Cash in Wallet
      - amount: 2.40
        account_id: Expenses:Dining
        memo: 4 whole grain buns

Implementation[edit]

The ledger model is implemented in Python, utilizing dataclasses and type hinting for clear and maintainable code. The `@lod_storable` decorator is used to enable easy serialization and deserialization of the data in YAML and/or JSON and other formats. The core idea is that the records should be readily available an tabular "list of dicts (lod)" format.

🖨 🚪