Create Posts “2023-01-19-postgres-dynamic-triggers-for-keeping-updated_at/index”

content/blog/2023-01-19-postgres-dynamic-triggers-for-keeping-updated_at/index.md

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+---
+layout: post
+visibility: public
+title: "Postgres: dynamic triggers for keeping updated_at"
+date: 2023-01-19T21:23:13.278Z
+---
+```
+CREATE OR REPLACE FUNCTION public.set_updated_at_now ()
+    RETURNS TRIGGER
+    AS $body$
+DECLARE
+    _q_txt text;
+BEGIN
+    NEW.updated_at = NOW();
+    RETURN NEW;
+END;
+$body$
+LANGUAGE plpgsql
+SECURITY DEFINER SET search_path = pg_catalog, public;
+
+CREATE OR REPLACE FUNCTION public.track_updated_at (target_table regclass)
+    RETURNS void
+    AS $body$
+DECLARE
+    _q_txt text;
+BEGIN
+    EXECUTE 'drop trigger if exists track_updated_at on ' || target_table;
+    _q_txt = 'create trigger track_updated_at before update on ' || target_table || ' for each row execute procedure public.set_updated_at_now();';
+    RAISE NOTICE '%', _q_txt;
+    EXECUTE _q_txt;
+END;
+$body$
+LANGUAGE 'plpgsql';
+
+COMMENT ON FUNCTION public.track_updated_at (regclass) IS $body$
+Set an automated trigger to set updated_at whenever UPDATE is called on a row in target_table.
+
+Arguments:
+   target_table:     Table name, schema qualified if not on search_path
+$body$;
+```
+
+Then use with
+
+```
+SELECT
+    track_updated_at ('api_keys');
+```