Oracle/Drop all user tables

-- v1
select 'drop table '||table_name||' cascade constraints;' from user_tables;

-- v2
BEGIN
  for c in (select table_name from user_tables) loop
    execute immediate ('drop table '||c.table_name||' cascade constraints');
  end loop;
END;

-- v3 (usable for other types too)
select 'drop table '||object_name||' cascade constraints;' from USER_OBJECTS where object_type = 'TABLE';