From 2dd6e7c0df25a8175f173fbc9a750bae31480647 Mon Sep 17 00:00:00 2001
From: "Karl O. Pinc kop@karlpinc.com" <kop@karlpinc.com>
Date: Wed, 20 May 2026 15:12:04 +0000
Subject: [PATCH] The individual consuming the food must be the focal

---
 db/schemas/lib/triggers/create/follows.m4 | 40 +++++++++++++++++++
 db/schemas/lib/triggers/create/roles.m4   | 47 +++++++++++++++++++++++
 doc/src/tables/events.m4                  |  6 +++
 3 files changed, 93 insertions(+)

diff --git a/db/schemas/lib/triggers/create/follows.m4 b/db/schemas/lib/triggers/create/follows.m4
index c2449a5..5e59cf4 100644
--- a/db/schemas/lib/triggers/create/follows.m4
+++ b/db/schemas/lib/triggers/create/follows.m4
@@ -529,6 +529,46 @@ CREATE OR REPLACE FUNCTION follows_func ()
     END;
   END IF;
 
+  IF TG_OP = 'UPDATE'
+     AND NEW.focal <> OLD.focal THEN
+
+    -- The individual eating must be the focal.
+    SELECT events.eid, events.behavior, events.start, events.stop
+         , roles.pid, roles.role, roles.participant
+      INTO a_eid     , a_behavior     , a_start     , a_stop
+         , a_pid    , a_role    , a_participant
+      FROM events
+             JOIN roles
+                  ON (roles.eid = events.eid)
+      WHERE events.fid = NEW.fid
+            AND events.behavior = 'sdb_food'
+            AND roles.participant <> NEW.focal;
+    IF FOUND THEN
+      RAISE EXCEPTION integrity_constraint_violation USING
+            MESSAGE = 'Error on UPDATE of FOLLOWS'
+          , DETAIL = 'The individual eating must the the focal'
+                     || ': Key (FID) = ('
+                     || NEW.fid
+                     || '), Value (Focal) = ('
+                     || NEW.focal
+                     || '), Value (Date) = ('
+                     || NEW.date
+                     || '): Key (EVENTS.EID) = ('
+                     || a_eid
+                     || '): Value (EVENTS.Behavior) = ('
+                     || a_behavior
+                     || '), Value (EVENTS.Start) = ('
+                     || a_start
+                     || '), Value (EVENTS.Stop) = ('
+                     || a_stop
+                     || '): Key (ROLES.PID) = ('
+                     || a_pid
+                     || '), Value (ROLES.Role) = ('
+                     || a_role
+                     || ')';
+    END IF;
+  END IF;
+
   RETURN NULL;
   END;
 $$;
diff --git a/db/schemas/lib/triggers/create/roles.m4 b/db/schemas/lib/triggers/create/roles.m4
index 4fb22b3..d366252 100644
--- a/db/schemas/lib/triggers/create/roles.m4
+++ b/db/schemas/lib/triggers/create/roles.m4
@@ -333,6 +333,53 @@ CREATE OR REPLACE FUNCTION roles_func ()
     END;
   END IF;
 
+  --
+  -- The participant must be the focal for food events
+  --
+  IF TG_OP = 'INSERT'
+     AND a_behavior = 'sdb_food' THEN
+    DECLARE
+      a_focal follows.focal%TYPE;
+      a_date follows.date%TYPE;
+      a_community follows.community%TYPE;
+
+    BEGIN
+      SELECT follows.focal, follows.date, follows.community
+        INTO a_focal      , a_date      , a_community
+        FROM follows
+        WHERE follows.fid = a_fid
+              AND NEW.participant <> follows.focal;
+      IF FOUND THEN
+        RAISE EXCEPTION integrity_constraint_violation USING
+              MESSAGE = 'Error on INSERT of ROLES'
+            , DETAIL = 'The individual eating must be the focal'
+                       || ': Key (PID) = ('
+                       || NEW.pid
+                       || '), Value (EID) = ('
+                       || NEW.eid
+                       || '), Value (Role) = ('
+                       || NEW.role
+                       || '), Value (Participant) = ('
+                       || NEW.participant
+                       || '), Value (EVENTS.Behavior) = ('
+                       || a_behavior
+                       || '), Value (EVENTS.Start) = ('
+                       || a_start
+                       || '), Value (EVENTS.Stop) = ('
+                       || a_stop
+                       || '), Value (FOLLOWS.FID) = ('
+                       || a_fid
+                       || '), Value (FOLLOWS.Focal) = ('
+                       || a_focal
+                       || '), Value (FOLLOWS.Date) = ('
+                       || a_date
+                       || '), Value (FOLLOWS.Community) = ('
+                       || a_community
+                       || ')';
+      END IF;
+    END;
+  END IF;
+
   --
   -- Depending on the behavior, when there are multiple participants
   -- each must be distinct.
diff --git a/doc/src/tables/events.m4 b/doc/src/tables/events.m4
index 781c0dc..fded63b 100644
--- a/doc/src/tables/events.m4
+++ b/doc/src/tables/events.m4
@@ -130,6 +130,12 @@ The following table lists these rules and implications:
    The system will generate a warning when there is no |ROLES| row
    related to the food event.
 
+   The individual consuming the food must be the the focal of the
+   follow.
+   This means that the |ROLES| row related to the event must have a
+   |ROLES|.\ |ROLES.Participant| value equal to the |FOLLOWS|.\
+   |FOLLOWS.Focal| of the follow that is related to the food event.
+
    The EVENTS.\ |EVENTS.Start| column contains the time the food bout
    began.
 
-- 
2.34.1