diff --git a/models/lms.model b/models/lms.model
index 7ee6b9da4..efd7549a2 100644
--- a/models/lms.model
+++ b/models/lms.model
@@ -40,12 +40,20 @@ Qualification
 --  - PinReset==1 mit bestehendem Passwort kann problemlos erneut gesendet werden
 --  - Flag "interner Mitarbeiter" wird von Know-How ignoriert / nicht ausgewertet (legacy)
 
-QualificationPrecondition
+QualificationPrecondition                       -- NOTE: this can only be enforced through a background job adding or removing qualifications
   qualification     QualificationId OnDeleteCascade OnUpdateCascade -- AND: not unique, ie. qualification can have multiple required preconditions
   required          [QualificationId]           -- OR : alternatives, any one will suffice
-  continuous        Bool                        -- expiring precondition removes qualification
+  continuous        Bool                        -- expiring precondition blocks qualification
   deriving Generic
 
+-- Maybe an alternative for online qualification validity checking, transitivity through recursive CTEs? (already available in our version)
+-- QualificationRequirement
+--   qualification     QualificationId OnDeleteCascade OnUpdateCascade
+--   requirement       QualificationId OnDeleteCascade OnUpdateCascade
+--   group             Text -- OR: several requirements within the same group are considered equivalent
+--   UniqueQualificationRequirement qualification requirement
+--
+
 -- TODO: connect Qualification with Exams!
 
 QualificationEdit