The most useles answer would be: Yes; run a recursive CTE query and if it does not terminate, then there are loops ;)
-----Ursprüngliche Nachricht----- Von: sqlite-users [mailto:sqlite-users-boun...@mailinglists.sqlite.org] Im Auftrag von Shane Dev Gesendet: Mittwoch, 20. Dezember 2017 22:32 An: SQLite mailing list <sqlite-users@mailinglists.sqlite.org> Betreff: [EXTERNAL] [sqlite] How to detect cycles in a hierarchical table? Hello, I have an edges table - sqlite> .sch edges CREATE TABLE edges(parent, child); sqlite> select * from edges; parent child 1 2 1 3 2 4 3 1 4 5 5 2 Here we have two cycles - 1) 1 => 3 => 1 (length 1) 2) 2 => 4 => 5 => 2 (length 3) Cycles cause recursive common table expression queries to become infinite loops. Is there a query which can detect all cycles regardless of length? _______________________________________________ sqlite-users mailing list sqlite-users@mailinglists.sqlite.org http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users ___________________________________________ Gunter Hick | Software Engineer | Scientific Games International GmbH | Klitschgasse 2-4, A-1130 Vienna | FN 157284 a, HG Wien, DVR: 0430013 | (O) +43 1 80100 - 0 May be privileged. May be confidential. Please delete if not the addressee. _______________________________________________ sqlite-users mailing list sqlite-users@mailinglists.sqlite.org http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users
