buybill

create table buybill(
buyid number,
buydate date default sysdate,
buytime date default sysdate,
buyinvoiceno varchar2(30),
buyimporter varchar2(30),
buycash varchar2(4) constraint buybill_buycash_cc check((buycash='yes') or (buycash='no')),
buypostpone varchar2(4) constraint buybill_buypostpone_cc check((buypostpone='yes') or (buypostpone='no')),
buyuser varchar2(30),
buytotalg number(7,3) default 0,
buytotalb number(7,3) default 0,
buyitemcount number(5),
buyearn number(7,3) default 0,
buyearnpercent number(5),
buyadd number(7,3) default 0,
buyminus number(7,3) default 0,
constraint buybill_buyid_pk primary key(buyid));

 importers

create table importers(
importerID number(5),
importername varchar2(30),
importerphone varchar2(30),
importeraddress varchar2(30),
importertype varchar2(30),
importerballance number(10,3) default 0,
importerdate date default sysdate,
importertime date default sysdate,
importeruser varchar2(30));

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 items
create table items(
itemid number ,
itembarcode varchar2(30),
itemname varchar2(30),
itemgroup varchar2(30),
itemcompany varchar2(30),
itemplace varchar2(30),
itemprice number(10,3) default 0,
itemqty number(5),
itemlimit number(5),
itemmaxdiscound number(5),
itemearn number(10),
itemdate default sysdate,
itemtime date default sysdate,
itemuser varchar2(30),
constraint items_itemname_pk primary key(itemname));
_______________________________________________
 operations

 create table operations(
 operid number primary key,
 buyid number,
 saleid number(10),
 rebuyid number(10),
 resaleid number(10),
 operitem varchar2(20),
 operitemexp date default sysdate,
 buyqty number(10,3) ,
 buytotalg number(10,3),
 buydiscound number(5),
 buyunitprice number(10,3),
 buytotalb number(10,3),
 buyearn number(10,3),
 buynotes varchar2(20),
 saleqty number(10,3),
 saletotalg number(10,3),
 salediscound number(5),
 saletotalb number(10,3),
 salenotes varchar2(20),
 rebuyqty number(10,3),
 rebuytotalg number(10,3),
 rebuynotes varchar2(20),
 resaleqty number(10,3),
 resaletotalg number(10,3),
 resalenotes varchar2(10),
 operdate date default sysdate,
 opertime date default sysdate,
 operuser varchar2(30));

_________________________________________________________________________
create sequence seq_autonumber;


create trigger trg_autonumber
before insert on operations
for each row
begin
  select seq_autonumber.nextval into :new.operid from dual;
end;
/