データベース名一覧、テーブル名一覧、カラム名一覧

SELECT datname FROM pg_database WHERE datistemplate = false;

SELECT table_name FROM information_schema.tables WHERE table_schema='public' AND table_type='BASE TABLE';

SELECT column_name , data_type , udt_name FROM information_schema.columns WHERE table_name = 'テーブル名' ORDER BY ordinal_position;