diff --git a/lib/transaction.rb b/lib/transaction.rb
index 921b9951c1f98c2d79f890f0576556d1846c0275..e4bce70f04bc4904ec08825e5e994a6aff4a41df 100644
--- a/lib/transaction.rb
+++ b/lib/transaction.rb
@@ -23,6 +23,20 @@ class Transaction
 		end
 	end
 
+	def delete
+		ids = [@transaction_id, "bonus_for_#{@transaction_id}"]
+		DB.query_defer(<<~SQL, ids)
+			DELETE FROM transactions WHERE transaction_id IN ($1, $2)
+		SQL
+	end
+
+	def exists?
+		DB.query_one(<<~SQL, @transaction_id).then { |r| r[:count] == 1 }
+			SELECT COUNT(1) FROM transactions
+			WHERE transaction_id = $1
+		SQL
+	end
+
 	def total
 		amount + bonus
 	end