Why should you care?

PostgresVerse core banking schema must never lose a rupee on partial failure or duplicate webhook.

See it live — copy this example

Run in pgAdmin or psql.

CREATE TABLE ledger_entries (
  entry_id bigserial PRIMARY KEY,
  account_id bigint NOT NULL,
  amount numeric(14,2) NOT NULL,
  direction char(1) CHECK (direction IN ('D','C')),
  transfer_id uuid NOT NULL,
  posted_at timestamptz DEFAULT now()
);
CREATE UNIQUE INDEX ON ledger_entries (transfer_id, account_id, direction);

What happened?

• Each transfer posts debit and credit lines sharing transfer_id.
• Unique index makes retry with same transfer_id idempotent — duplicate insert fails safely.

Practice next

1. Create ledger_entries in PostgresVerse core schema.
2. Wrap debit/credit INSERT in BEGIN ... COMMIT with shared transfer_id.
3. Retry same transfer_id and observe unique violation.
4. Add CHECK that sum of credits equals debits per transfer_id via trigger.
5. Query running balance with window SUM OVER account_id.

Remember

Ledger append-only; corrections are reversing entries. Idempotency keys prevent duplicate transfers. Numeric type and CHECK enforce valid directions.

PostgresVerse NEFT retry

Gateway timeout retries payment; unique on transfer_id blocks double debit.

Outcome: Customer charged once; support ticket avoided.