drop table "address" cascade constraints;
drop table "comment" cascade constraints;
drop table "file" cascade constraints;
drop table "file_ext" cascade constraints;
drop table "group" cascade constraints;
drop table "message" cascade constraints;
drop table "post" cascade constraints;
drop table "post_like" cascade constraints;
drop table "role" cascade constraints;
drop table "subject" cascade constraints;
drop table "user" cascade constraints;
drop table "user_comment" cascade constraints;
drop table "user_group" cascade constraints;
drop table "user_subject" cascade constraints;