History for Interesting validation rules

Revisions
 Nigel Stanger on 7 Oct 2021 : Added PL/pgSQL implementation
 Nigel Stanger on 23 Aug 2021 : Updated Interesting validation rules
 Nigel Stanger on 6 Aug 2021 : Updated Interesting validation rules
 Nigel Stanger on 6 Aug 2021 : Updated Interesting validation rules
 Nigel Stanger on 6 Aug 2021 : Updated Interesting validation rules
 Nigel Stanger on 6 Aug 2021 : Updated Interesting validation rules
 Nigel Stanger on 6 Aug 2021 : Updated Interesting validation rules
 Nigel Stanger on 6 Aug 2021 : Added Java implementation
 Nigel Stanger on 10 Sep 2020 : Added validation rules