diff --git a/book/src/dev/rfcs/0005-state-updates.md b/book/src/dev/rfcs/0005-state-updates.md
index d8db68eb..3692cb02 100644
--- a/book/src/dev/rfcs/0005-state-updates.md
+++ b/book/src/dev/rfcs/0005-state-updates.md
@@ -600,7 +600,7 @@ We use the following Sled trees:
 | `hash_by_height`     | `BE32(height)`        | `block::Hash`                       |
 | `height_by_hash`     | `block::Hash`         | `BE32(height)`                      |
 | `block_by_height`    | `BE32(height)`        | `Block`                             |
-| `tx_by_hash`         | `transaction::Hash`   | `BE32(height) || BE32(tx_index)`    |
+| `tx_by_hash`         | `transaction::Hash`   | `(BE32(height), BE32(tx_index))`    |
 | `utxo_by_outpoint`   | `OutPoint`            | `TransparentOutput`                 |
 | `sprout_nullifiers`  | `sprout::Nullifier`   | `()`                                |
 | `sapling_nullifiers` | `sapling::Nullifier`  | `()`                                |