academy=> \d invoice;
                                      Table "public.invoice"
   Column    |            Type             |                      Modifiers
-------------+-----------------------------+------------------------------------------------------
 id          | integer                     | not null default nextval('invoice_id_seq'::regclass)
 number      | bytea                       | not null
 due_date    | timestamp without time zone | not null
 amount      | integer                     | not null
 paid        | boolean                     | not null default false
 model       | bytea                       | not null
 model_id    | integer                     | not null
 student_id  | integer                     | not null
 previous_id | integer                     |
 note        | text                        | not null default ''::text
Indexes:
    "invoice_pkey" PRIMARY KEY, btree (id)
    "invoice_number_idx" btree (number)
Foreign-key constraints:
    "invoice_previous_id_fkey" FOREIGN KEY (previous_id) REFERENCES invoice(id) ON DELETE RESTRICT
    "invoice_student_id_fkey" FOREIGN KEY (student_id) REFERENCES student(id) ON DELETE RESTRICT
Referenced by:
    TABLE "invoice" CONSTRAINT "invoice_previous_id_fkey" FOREIGN KEY (previous_id) REFERENCES invoice(id) ON DELETE RESTRICT
    TABLE "receipt_invoice" CONSTRAINT "receipt_invoice_invoice_id_fkey" FOREIGN KEY (invoice_id) REFERENCES invoice(id) ON DELETE CASCADE





academy=> \d receipt;
                                                        Table "public.receipt"
    Column     |            Type             |                                       Modifiers
---------------+-----------------------------+----------------------------------------------------------------------------------------
 id            | integer                     | not null default nextval('receipt_id_seq'::regclass)
 creator_id    | integer                     | not null
 datetime      | timestamp without time zone | not null default now()
 number        | integer                     | not null
 receipt_date  | date                        | not null
 html          | text                        |
 random_number | integer                     | not null default trunc(((random() * (999)::double precision) + (1)::double precision))
Indexes:
    "receipt_pkey" PRIMARY KEY, btree (id)
    "number_idx" UNIQUE, btree (date_part('month'::text, datetime), date_part('year'::text, datetime), number)
Foreign-key constraints:
    "receipt_creator_id_fkey" FOREIGN KEY (creator_id) REFERENCES warp_avatar(id) ON DELETE RESTRICT
Referenced by:
    TABLE "receipt_invoice" CONSTRAINT "receipt_invoice_receipt_id_fkey" FOREIGN KEY (receipt_id) REFERENCES receipt(id) ON DELETE CASCADE

academy=> \d receipt_invoice;
  Table "public.receipt_invoice"
   Column   |  Type   | Modifiers
------------+---------+-----------
 receipt_id | integer | not null
 invoice_id | integer | not null
Indexes:
    "receipt_invoice_idx" UNIQUE, btree (receipt_id, invoice_id)
    "invoice_id_idx" btree (invoice_id)
    "receipt_id_idx" btree (receipt_id)
Foreign-key constraints:
    "receipt_invoice_invoice_id_fkey" FOREIGN KEY (invoice_id) REFERENCES invoice(id) ON DELETE CASCADE
    "receipt_invoice_receipt_id_fkey" FOREIGN KEY (receipt_id) REFERENCES receipt(id) ON DELETE CASCADE


academy=> \d adhoc_balance;
                                        Table "public.adhoc_balance"
     Column      |            Type             |                         Modifiers
-----------------+-----------------------------+------------------------------------------------------------
 id              | integer                     | not null default nextval('adhoc_balance_id_seq'::regclass)
 expense         | text                        | not null
 balance         | integer                     | not null
 created         | timestamp without time zone | not null
 student_id      | integer                     | not null
 total_amount    | integer                     |
 original_amount | integer                     |
Indexes:
    "adhoc_balance_pkey" PRIMARY KEY, btree (id)
Foreign-key constraints:
    "adhoc_balance_student_id_fkey" FOREIGN KEY (student_id) REFERENCES student(id) ON DELETE CASCADE


                List of relations
 Schema |         Name         | Type  |  Owner
--------+----------------------+-------+---------
 public | adhoc_balance        | table | academy
 public | attendance           | table | academy
 public | class                | table | academy
 public | class_time           | table | academy
 public | contact_type         | table | academy
 public | course               | table | academy
 public | course_level         | table | academy
 public | history              | table | academy
 public | intended_course_type | table | academy
 public | invoice              | table | academy
 public | lesson               | table | academy
 public | receipt              | table | academy
 public | receipt_invoice      | table | academy
 public | room                 | table | academy
 public | schedule             | table | academy
 public | stateful_grid        | table | academy
 public | student              | table | academy
 public | student_class        | table | academy
 public | wait_list            | table | academy
 public | warp_avatar          | table | academy
 public | warp_avatar_role     | table | academy
 public | warp_fulltext        | table | academy
 public | warp_session         | table | academy
(23 rows)