Truncate all the tables of 'public' schema

truncate_all_tables.sql

CREATE OR REPLACE FUNCTION truncate_all_tables() RETURNS void AS $$
DECLARE
    stmt RECORD;
    statements CURSOR FOR SELECT tablename from pg_tables where schemaname = 'public';
BEGIN
    FOR stmt IN statements LOOP
        EXECUTE 'TRUNCATE TABLE ' || quote_ident(stmt.tablename) || ' CASCADE;';
    END LOOP;
END;                         
$$ LANGUAGE 'plpgsql';