create extension if not exists btree_gist; create extension if not exists pgcrypto; create or replace language plpgsql; create or replace language plpython3u; create or replace function hash_sha1(text) returns text as $$ select encode(digest($1, 'sha1'), 'hex') $$ language sql strict immutable; comment on function hash_sha1(text) is 'Compute sha1 hash as text';