Goal Find triggers that try prevent updating data in a certain column but prevent also certain legal updates - updates that write to a field a value that was in the field before the update.
Notes Find row level BEFORE triggers that raise a warning or error but do not have any condition - in the function nor in the WHEN clause of the trigger.
Type Problem detection (Each row in the result could represent a flaw in the design)
Reliability Medium (Medium number of false-positive results)
License MIT (opens in new tab)
Fixing Suggestion Add a condition to the WHEN clause of the trigger. For instance, if we want to prevent changing the registration time and the registrator, then the trigger should have the WHEN clause: WHEN (OLD.registration_time<>NEW.registration_time OR OLD.registrator_id<>NEW.registrator_id)
Data Source INFORMATION_SCHEMA+system catalog
SQL Query 
WITH Tr AS (SELECT
    n.nspname AS trigger_schema,
    t.tgname AS trigger_name,
    em.text AS event_manipulation,        
    c.relname AS trigger_table, 
    np.nspname AS routine_schema,
    p.proname AS routine_name,
     p.prosrc AS routine_definition,
     (SELECT DISTINCT action_condition FROM INFORMATION_SCHEMA.triggers AS it WHERE it.trigger_schema=n.nspname AND it.event_object_table=c.relname AND it.trigger_name=t.tgname) AS action_condition,    
        CASE t.tgtype::integer & 1
            WHEN 1 THEN 'ROW'
            ELSE 'STATEMENT'
        END AS action_orientation,
        CASE t.tgtype::integer & 66
            WHEN 2 THEN 'BEFORE'
            WHEN 64 THEN 'INSTEAD OF'
            ELSE 'AFTER'
        END AS action_timing	
   FROM pg_namespace n,
    pg_class c,
    pg_trigger t,
    pg_proc p,
    pg_namespace np,
    ( VALUES (4,'INSERT'), (8,'DELETE'), (16,'UPDATE'), (32,'TRUNCATE')) em(num, text)
  WHERE n.oid = c.relnamespace 
  AND c.oid = t.tgrelid 
  AND t.tgfoid=p.oid
  AND p.pronamespace=np.oid
  AND (t.tgtype::integer & em.num) <> 0 
  AND NOT t.tgisinternal 
  AND NOT pg_is_other_temp_schema(n.oid))
SELECT trigger_schema, trigger_table, action_timing, event_manipulation, action_orientation, action_condition, routine_name, regexp_replace(routine_definition,'[\r\n]','<br>','g')  AS routine_definition
FROM Tr
WHERE action_orientation='ROW' 
AND action_timing='BEFORE'
AND event_manipulation='UPDATE'
AND routine_definition~* '[[:space:]]+(WARNING|EXCEPTION)[[:space:]]+'
AND routine_definition!~* 'IF[[:space:]][^;]*[(OLD|NEW)[^;]*(OLD|NEW).*[[:space:]]+(WARNING|EXCEPTION)[[:space:]]+'
AND (action_condition !~*'(OLD|NEW).*(OLD|NEW)' OR action_condition IS NULL)
ORDER BY trigger_schema, trigger_table, routine_name;

Collections

This query belongs to the following collections:

Find problems automatically

Queries, that results point to problems in the database. Each query in the collection produces an initial assessment. However, a human reviewer has the final say as to whether there is a problem or not .

NameDescription
Find problems automaticallyQueries, that results point to problems in the database. Each query in the collection produces an initial assessment. However, a human reviewer has the final say as to whether there is a problem or not .

Categories

This query is classified under the following categories:

Triggers and rules

Queries of this category provide information about triggers and rules in a database.

NameDescription
Triggers and rulesQueries of this category provide information about triggers and rules in a database.