domain-fintech:financial-data-modeling
Guides financial data modeling: account structures (asset, liability, equity, revenue, expense), currency handling (ISO 4217, minor units), decimal precision (BigDecimal, integer cents), multi-currency ledgers, financial instrument representation, and temporal data patterns. Use when designing da...
SKILL.md
Full skill instructions
Financial Data Modeling
When to use
- Designing database schemas for accounting or banking applications
- Choosing the right numeric type for monetary storage
- Modeling multi-currency accounts with FX gain/loss tracking
- Representing financial instruments (bonds, equities, derivatives)
- Implementing point-in-time queries and bi-temporal history
- Enforcing data integrity rules for financial records
Core principles
- Never float money — use
DECIMAL(19,4)or integer minor units; floating point errors compound - Currency is always explicit — every amount must carry its ISO 4217 currency code
- Soft-delete only — status flags and effective dates, never DELETE financial records
- Bi-temporal when auditability demands it — system time tracks inserts, business time tracks validity
- Cost basis per lot — position tracking must support FIFO/LIFO/weighted average for tax reporting
Reference Files
references/account-structures-currency.md— chart of accounts hierarchy, account model design, ISO 4217 compliance, floating-point avoidance, rounding rules per jurisdictionreferences/multi-currency-instruments.md— exchange rate management, multi-currency schema, realized vs unrealized FX gains, financial instrument hierarchy, position trackingreferences/temporal-data-integrity.md— effective dating, as-of queries, bi-temporal schema pattern, and data integrity constraints for financial tables