sqldb: Change payment_intent relationship to payment table

Previously a one(intent)-to-many(payment) relationship it is now
changed to a one-to-one relationship because a payment request
only can have 1 payment related to it. Looking into the future
with BOLT12 offers, the fetched invoice from the offer could be
stored here as well and the relationship would still hold.

sqldb/sqlc/migrations/000009_payments.up.sql

@@ -2,43 +2,12 @@
 -- Payment System Schema Migration
 -- ─────────────────────────────────────────────
 -- This migration creates the complete payment system schema including:
--- - Payment intents (BOLT 11/12 invoices, offers)
+-- - Payment intents (only BOLT 11 invoices for now)
 -- - Payment attempts and HTLC tracking
 -- - Route hops and custom TLV records
 -- - Resolution tracking for settled/failed payments
 -- ─────────────────────────────────────────────
 
--- ─────────────────────────────────────────────
--- Payment Intents Table
--- ─────────────────────────────────────────────
--- Stores the descriptor of what the payment is paying for.
--- Depending on the type, the payload might contain:
--- - BOLT 11 invoice data
--- - BOLT 12 offer data  
--- - NULL for legacy hash-only/keysend style payments
--- ─────────────────────────────────────────────
-
-CREATE TABLE IF NOT EXISTS payment_intents (
-    -- Primary key for the intent record
-    id INTEGER PRIMARY KEY,
-
-    -- The type of intent (e.g. 0 = bolt11_invoice, 1 = bolt12_offer)
-    -- Uses SMALLINT (int16) for efficient storage of enum values
-    intent_type SMALLINT NOT NULL,
-
-    -- The serialized payload for the payment intent
-    -- Content depends on type - could be invoice, offer, or NULL
-    intent_payload BLOB
-);
-
--- Index for efficient querying by intent type
-CREATE INDEX IF NOT EXISTS idx_payment_intents_type
-ON payment_intents(intent_type);
-
--- Unique constraint for deduplication of payment intents
-CREATE UNIQUE INDEX IF NOT EXISTS idx_payment_intents_unique
-ON payment_intents(intent_type, intent_payload);
-
 -- ─────────────────────────────────────────────
 -- Payments Table
 -- ─────────────────────────────────────────────
@@ -55,10 +24,6 @@ CREATE TABLE IF NOT EXISTS payments (
     -- Primary key for the payment record
     id INTEGER PRIMARY KEY,
 
-    -- Optional reference to the payment intent this payment was derived from
-    -- Links to BOLT 11 invoice, BOLT 12 offer, etc.
-    intent_id BIGINT REFERENCES payment_intents (id),
-
     -- The amount of the payment in millisatoshis
     amount_msat BIGINT NOT NULL,
 
@@ -84,6 +49,45 @@ CREATE TABLE IF NOT EXISTS payments (
 CREATE INDEX IF NOT EXISTS idx_payments_created_at
 ON payments(created_at);
 
+-- ─────────────────────────────────────────────
+-- Payment Intents Table
+-- ─────────────────────────────────────────────
+-- Stores the descriptor of what the payment is paying for.
+-- Depending on the type, the payload might contain:
+-- - BOLT 11 invoice data
+-- - BOLT 12 offer data
+-- - NULL for legacy hash-only/keysend style payments
+-- ─────────────────────────────────────────────
+
+CREATE TABLE IF NOT EXISTS payment_intents (
+    -- Primary key for the intent record
+    id INTEGER PRIMARY KEY,
+
+    -- Reference to the payment this intent belongs to (one-to-one relationship)
+    -- When the payment is deleted, the intent is automatically deleted
+    payment_id BIGINT NOT NULL REFERENCES payments (id) ON DELETE CASCADE,
+
+    -- The type of intent (e.g. 0 = bolt11_invoice, 1 = bolt12_invoice)
+    -- Uses SMALLINT (int16) for efficient storage of enum values
+    intent_type SMALLINT NOT NULL,
+
+    -- The serialized payload for the payment intent
+    -- Content depends on type - could be invoice, offer, or NULL
+    intent_payload BLOB,
+
+    -- Ensure one-to-one relationship: each payment has at most one intent.
+    -- Currently we only support one intent per payment this makes sure we do
+    -- not accidentally pay the same request multiple times. This currently
+    -- only has bolt 11 payment requests/invoices. But in the future this can
+    -- also include BOLT 12 offers/invoices.
+    CONSTRAINT idx_payment_intents_payment_id_unique
+    UNIQUE (payment_id)
+);
+
+-- Index for efficient querying by intent type
+CREATE INDEX IF NOT EXISTS idx_payment_intents_type
+ON payment_intents(intent_type);
+
 -- ─────────────────────────────────────────────
 -- Payment HTLC Attempts Table
 -- ─────────────────────────────────────────────

sqldb/sqlc/models.go

@@ -211,7 +211,6 @@ type MigrationTracker struct {
 
 type Payment struct {
 	ID                int64
-	IntentID          sql.NullInt64
 	AmountMsat        int64
 	CreatedAt         time.Time
 	PaymentIdentifier []byte
@@ -264,6 +263,7 @@ type PaymentHtlcAttemptResolution struct {
 
 type PaymentIntent struct {
 	ID            int64
+	PaymentID     int64
 	IntentType    int16
 	IntentPayload []byte
 }

sqldb/sqlc/payments.sql.go

@@ -317,11 +317,11 @@ func (q *Queries) FetchHtlcAttemptsForPayments(ctx context.Context, paymentIds [
 
 const fetchPayment = `-- name: FetchPayment :one
 SELECT
-    p.id, p.intent_id, p.amount_msat, p.created_at, p.payment_identifier, p.fail_reason,
+    p.id, p.amount_msat, p.created_at, p.payment_identifier, p.fail_reason,
     i.intent_type AS "intent_type",
     i.intent_payload AS "intent_payload"
 FROM payments p
-LEFT JOIN payment_intents i ON i.id = p.intent_id
+LEFT JOIN payment_intents i ON i.payment_id = p.id
 WHERE p.payment_identifier = $1
 `
 
@@ -336,7 +336,6 @@ func (q *Queries) FetchPayment(ctx context.Context, paymentIdentifier []byte) (F
 	var i FetchPaymentRow
 	err := row.Scan(
 		&i.Payment.ID,
-		&i.Payment.IntentID,
 		&i.Payment.AmountMsat,
 		&i.Payment.CreatedAt,
 		&i.Payment.PaymentIdentifier,
@@ -398,11 +397,11 @@ func (q *Queries) FetchPaymentLevelFirstHopCustomRecords(ctx context.Context, pa
 
 const fetchPaymentsByIDs = `-- name: FetchPaymentsByIDs :many
 SELECT
-    p.id, p.intent_id, p.amount_msat, p.created_at, p.payment_identifier, p.fail_reason,
+    p.id, p.amount_msat, p.created_at, p.payment_identifier, p.fail_reason,
     i.intent_type AS "intent_type",
     i.intent_payload AS "intent_payload"
 FROM payments p
-LEFT JOIN payment_intents i ON i.id = p.intent_id
+LEFT JOIN payment_intents i ON i.payment_id = p.id
 WHERE p.id IN (/*SLICE:payment_ids*/?)
 `
 
@@ -433,7 +432,6 @@ func (q *Queries) FetchPaymentsByIDs(ctx context.Context, paymentIds []int64) ([
 		var i FetchPaymentsByIDsRow
 		if err := rows.Scan(
 			&i.Payment.ID,
-			&i.Payment.IntentID,
 			&i.Payment.AmountMsat,
 			&i.Payment.CreatedAt,
 			&i.Payment.PaymentIdentifier,
@@ -510,11 +508,11 @@ const filterPayments = `-- name: FilterPayments :many
 */
 
 SELECT
-    p.id, p.intent_id, p.amount_msat, p.created_at, p.payment_identifier, p.fail_reason,
+    p.id, p.amount_msat, p.created_at, p.payment_identifier, p.fail_reason,
     i.intent_type AS "intent_type",
     i.intent_payload AS "intent_payload"
 FROM payments p
-LEFT JOIN payment_intents i ON i.id = p.intent_id
+LEFT JOIN payment_intents i ON i.payment_id = p.id
 WHERE (
     p.id > $1 OR
     $1 IS NULL
@@ -572,7 +570,6 @@ func (q *Queries) FilterPayments(ctx context.Context, arg FilterPaymentsParams)
 		var i FilterPaymentsRow
 		if err := rows.Scan(
 			&i.Payment.ID,
-			&i.Payment.IntentID,
 			&i.Payment.AmountMsat,
 			&i.Payment.CreatedAt,
 			&i.Payment.PaymentIdentifier,

sqldb/sqlc/queries/payments.sql

@@ -9,7 +9,7 @@ SELECT
     i.intent_type AS "intent_type",
     i.intent_payload AS "intent_payload"
 FROM payments p
-LEFT JOIN payment_intents i ON i.id = p.intent_id
+LEFT JOIN payment_intents i ON i.payment_id = p.id
 WHERE (
     p.id > sqlc.narg('index_offset_get') OR
     sqlc.narg('index_offset_get') IS NULL
@@ -37,7 +37,7 @@ SELECT
     i.intent_type AS "intent_type",
     i.intent_payload AS "intent_payload"
 FROM payments p
-LEFT JOIN payment_intents i ON i.id = p.intent_id
+LEFT JOIN payment_intents i ON i.payment_id = p.id
 WHERE p.payment_identifier = $1;
 
 -- name: FetchPaymentsByIDs :many
@@ -46,7 +46,7 @@ SELECT
     i.intent_type AS "intent_type",
     i.intent_payload AS "intent_payload"
 FROM payments p
-LEFT JOIN payment_intents i ON i.id = p.intent_id
+LEFT JOIN payment_intents i ON i.payment_id = p.id
 WHERE p.id IN (sqlc.slice('payment_ids')/*SLICE:payment_ids*/);
 
 -- name: CountPayments :one