PostingRule Entity

The PostingRule entity defines the specific rules for how financial transactions are posted to accounts within the double-entry bookkeeping system. Each posting rule specifies which account should be affected and whether the posting should be a debit (positive) or credit (negative) entry.

Properties

Schema

{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "type": "object",
  "title": "PostingRule",
  "description": "Defines the rules for posting transactions to specific accounts with appropriate signs (debit/credit)",
  "properties": {
    "id": {
      "type": "integer",
      "description": "Unique identifier for the posting rule (auto-generated primary key)",
      "example": 15827
    },
    "sign": {
      "type": "string",
      "enum": ["POSITIVE", "NEGATIVE"],
      "description": "Indicates whether the posting is POSITIVE (debit) or NEGATIVE (credit)",
      "example": "NEGATIVE"
    },
    "account_definition_fk": {
      "type": "integer",
      "description": "Foreign key reference to the target account definition",
      "example": 15652
    },
    "transaction_definition_fk": {
      "type": "integer",
      "description": "Foreign key reference to the parent transaction definition",
      "example": 15825
    }
  },
  "required": ["id"],
  "additionalProperties": false
}

Double-Entry Bookkeeping

PostingRules enforce the fundamental principle of double-entry bookkeeping where:

• Every transaction affects at least two accounts
• Total debits must equal total credits
• Account balances are maintained accurately through proper sign application

Sign Convention

The sign attribute determines the impact on account balances:

• POSITIVE: Increases asset and expense accounts, decreases liability, equity, and revenue accounts
• NEGATIVE: Decreases asset and expense accounts, increases liability, equity, and revenue accounts

Account Type Interactions

Different account types respond differently to positive and negative postings:

Asset Accounts (1xxx)

• Positive postings increase the asset value
• Negative postings decrease the asset value

Liability Accounts (2xxx)

• Positive postings decrease the liability (payment toward debt)
• Negative postings increase the liability (new debt)

Revenue Accounts (4xxx)

• Positive postings decrease revenue (reversals)
• Negative postings increase revenue (new income)

Expense Accounts (5xxx)

• Positive postings increase expenses
• Negative postings decrease expenses (reversals)

Usage in Transaction Processing

When a transaction is processed:

1. The system retrieves all posting rules for the transaction type
2. For each rule, it applies the specified amount with the appropriate sign
3. The posting is made to the target account specified in the rule
4. Balance validation ensures the transaction maintains accounting equation balance

Business Examples

Charge Transaction

• Rule 1: Post NEGATIVE to MerchantDebt (increases liability)
• Rule 2: Post POSITIVE to PSPReceivable (increases asset)

Refund Transaction

• Rule 1: Post POSITIVE to MerchantDebt (decreases liability)
• Rule 2: Post NEGATIVE to PSPReceivable (decreases asset)

Validation Rules

• Each posting rule must reference a valid account definition
• Sign must be either POSITIVE or NEGATIVE
• Rules must be associated with a valid transaction definition
• Account types must be compatible with the intended posting direction