-fix foreign key constraint issue

src/exchangedb/pg_do_purse_deposit.c

@@ -42,7 +42,9 @@ TEH_PG_do_purse_deposit (
   struct GNUNET_TIME_Timestamp reserve_expiration;
   uint64_t partner_id = 0; /* FIXME #7271: WAD support... */
   struct GNUNET_PQ_QueryParam params[] = {
-    GNUNET_PQ_query_param_uint64 (&partner_id),
+    (0 == partner_id)
+    ? GNUNET_PQ_query_param_null ()
+    : GNUNET_PQ_query_param_uint64 (&partner_id),
     GNUNET_PQ_query_param_auto_from_type (purse_pub),
     TALER_PQ_query_param_amount (amount),
     GNUNET_PQ_query_param_auto_from_type (coin_pub),

src/exchangedb/pg_insert_purse_request.c

@@ -63,8 +63,6 @@ TEH_PG_insert_purse_request (
   };
 
   *in_conflict = false;
-
-
   PREPARE (pg,
            "insert_purse_request",
            "INSERT INTO purse_requests"
@@ -79,7 +77,6 @@ TEH_PG_insert_purse_request (
            "  ,amount_with_fee_val"
            "  ,amount_with_fee_frac"
            "  ,purse_fee_val"
-
            "  ,purse_fee_frac"
            "  ,purse_sig"
            "  ) VALUES "
@@ -127,8 +124,3 @@ TEH_PG_insert_purse_request (
     return GNUNET_DB_STATUS_SUCCESS_ONE_RESULT;
   }
 }
-
-
-
-
-

src/exchangedb/procedures.sql

@@ -1654,7 +1654,7 @@ BEGIN
 
 IF in_partner_url IS NULL
 THEN
-  my_partner_serial_id=0;
+  my_partner_serial_id=NULL;
 ELSE
   SELECT
     partner_serial_id
@@ -1817,7 +1817,6 @@ ELSE
 
 END IF;
 
-
 RETURN;
 
 END $$;
@@ -1851,7 +1850,7 @@ INSERT INTO exchange.purse_merges
     ,merge_sig
     ,merge_timestamp)
   VALUES
-    (0
+    (NULL
     ,in_reserve_pub
     ,in_purse_pub
     ,in_merge_sig