Postgres: Recreate TRIGGER after replacing function?

Question

Given a function like this:

CREATE OR REPLACE FUNCTION foo()
RETURNS TRIGGER AS $$
BEGIN
 -- do something fancy
END;
$$
LANGUAGE plpgsql;

which is used in a TRIGGER:

CREATE TRIGGER bar
 BEFORE INSERT
 ON test
 FOR each ROW
 EXECUTE PROCEDURE foo();

Does the TRIGGER need to be re-created (DROP + CREATE) if the function foo() is changed (using REPLACE)?

Was coming across this while reading about partitioning.

• András Váczi: No, you can simply replace the function. Why not test it yourself?
• kev: I tried, but I got confused by an example that I found somewhere. Can't recollect where I saw it unfortunately. Now I even found it in the official docs: "The trigger definition does not need to be updated, however." here

Answer 1

-- Create the function foo()
CREATE OR REPLACE FUNCTION foo()
RETURNS TRIGGER AS $$
BEGIN
 -- do something fancy
 -- You should include the appropriate logic here.
 RETURN NEW; -- For example, return NEW; if it's a row-level trigger.
END;
$$
LANGUAGE plpgsql;
-- Create the trigger bar
CREATE TRIGGER bar
 BEFORE INSERT
 ON test
 FOR EACH ROW
 EXECUTE PROCEDURE foo();

use the CREATE OR REPLACE FUNCTION syntax to modify the function foo(), the trigger bar will automatically use the updated function without needing to be re-created (DROP + CREATE). The trigger will automatically reference the latest version of the function definition.