diff --git a/CHANGELOG.md b/CHANGELOG.md
new file mode 100644
index 0000000000000000000000000000000000000000..4a54a853961591182de86aa3ecbb52c2d0d07c57
--- /dev/null
+++ b/CHANGELOG.md
@@ -0,0 +1,19 @@
+# Changelog #
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+
+## [Unreleased] ##
+
+### Added ###
+
+### Changed ###
+
+### Deprecated ###
+
+### Fixed ###
+
+- Fixed several bugs when an Entity inherits from itself (#18, caosdb-server #85).
diff --git a/procedures/insertIsaCache.sql b/procedures/insertIsaCache.sql
index a4490bd24da11cdb4d0af5930bdeb14c3882925d..68c380865fe21b0a752e6136d2984f2748afb2fe 100644
--- a/procedures/insertIsaCache.sql
+++ b/procedures/insertIsaCache.sql
@@ -47,6 +47,7 @@ insert_is_a_proc: BEGIN
         -- Any additional entries would be redundant.
         LEAVE insert_is_a_proc;
     END IF;
+    -- Note: also for the next insertions, ignore existing lines with p == c
 
     -- Insert ancestors older than parents:
     -- for each supertype of p