Generating Slugs in Postgres

slugify.sql

CREATE EXTENSION IF NOT EXISTS "unaccent";

CREATE OR REPLACE FUNCTION slugify(t text) RETURNS text
AS $$
BEGIN
  t := lower(t);
  -- german
  t := replace(t, 'ä', 'ae');
  t := replace(t, 'ö', 'oe');
  t := replace(t, 'ü', 'ue');
  t := unaccent(t);
  -- cyrillic
  t := replace( replace( replace( replace(
replace( replace( replace( replace( translate(t,
'абвгдезийклмнопрстуфхцэы', 'abvgdezijklmnoprstufхcey'), 'ж', 'zh'),
'ч', 'ch'), 'ш', 'sh'), 'щ', 'shh'), 'ъ', ''), 'ю', 'yu'), 'я', 'ya'), 'ь', '');
  -- greek
  t := replace(t, 'ει', 'i');
  t := replace(t, 'οι', 'i');
  t := replace(t, 'θ', 'th');
  t := replace(t, 'ξ', 'ks');
  t := replace(t, 'χ', 'ch');
  t := translate(t, 'αβγδεζηικλμνοπρσςτυφω','abgdeziiklmnoprsstyfo');
  -- remove symbols
  t := regexp_replace(t, '[''"]+', '', 'gi');
  t := regexp_replace(t, '[^a-z0-9\\-_]+', '-', 'gi');
  t := regexp_replace(t, '\-+$', '');
  t := regexp_replace(t, '^\-', '');
  RETURN t;
END;
$$ LANGUAGE plpgsql STRICT IMMUTABLE PARALLEL SAFE;

slugify_trigger.sql

CREATE FUNCTION public.set_slug_from_name() RETURNS trigger
    LANGUAGE plpgsql
    AS $$
BEGIN
  NEW.slug := slugify(NEW.name);
  RETURN NEW;
END
$$;

CREATE TRIGGER "trg_slug_insert"
BEFORE INSERT ON "my_table_name"
FOR EACH ROW
WHEN (NEW.name IS NOT NULL AND NEW.slug IS NULL)
EXECUTE PROCEDURE set_slug_from_name();