These trigger functions automatically compute a tsvector column from one or more textual columns,
under the control of parameters specified in the CREATE TRIGGER command. An example of their use
is:
CREATE TABLE messages (
title text,
body text,
tsv tsvector
);
CREATE TRIGGER tsvectorupdate BEFORE INSERT OR UPDATE
ON messages FOR EACH ROW EXECUTE PROCEDURE
tsvector_update_trigger(tsv, 'pg_catalog.english', title, body);
INSERT INTO messages VALUES('title here', 'the body text is here');
SELECT * FROM messages;
title | body | tsv
------------+-----------------------+----------------------------
title here | the body text is here | 'bodi':4 'text':5 'titl':1
SELECT title, body FROM messages WHERE tsv @@ to_tsquery('title & body');
title | body
------------+-----------------------
title here | the body text is here
Having created this trigger, any change in title or body
will automatically be reflected into tsv, without the application having to worry
about it.