PL/Sql query execution error - oracle

Question

This is my query. A Trigger which automatically stores in a separate table called ‘ExcellentSale’ the Sales Agent
name, car model and manufacturer name, each time the agreed price of a
SalesTransaction is more than 20% of the car’s asking price. (Note: You need to create
the ‘ExcellentSale’ table before implementing this trigger. To create the primary key, use a
sequence that starts at 1 and increments by 1). It shows error like this
ERROR at line 23: PL/SQL: ORA-00942: table or view does not exist
1. create or replace trigger filltable
2. after insert on salestransaction
3. for each row
4. declare
The code for the trigger is:
create or replace trigger filltable
after insert on salestransaction
for each row
declare
aname varchar2(25);
modname varchar2(25);
manfname varchar2(25);
askpr number;
agrpr number;
begin
select sa.name,m.name,mf.name
into aname,modname,manfname
from manufacturer mf,model m, car c, salestransaction st, salesagent sa
where mf.manufacturerid = m.manufacturerid and
m.modelno = c.modelno and
c.vin = st.vin and
st.agentid = sa.agentid;
select askingprice,agreedprice
into askpr,agrpr
from car c,salestransaction st
where c.VIN = St.vin;
if(agrpr > askpr*1.2) then
insert into excellentsales values(agent_seq.nextval,aname,modname,manfname);
end if;
end filltable;
/
create table excellentsales
(agentid varchar2(5) not null,
agentname varchar2(25),
carmodel varchar2(25),
mfname varchar2(25),
primary key(agentid))
CREATE SEQUENCE agent_seq START WITH 1 INCREMENT BY 1;

Answer 1

You don't need to query SALESTRANSACTION within a row trigger on SALESTRANSACTION - you should instead be using the :NEW values on the SALESTRANSACTION row for which the trigger was invoked. I suggest rewriting your trigger as:
create table excellentsales
(EXCELLENTSALES_ID NUMBER
CONSTRAINT PK_EXCELLENTSALES
PRIMARY KEY
USING INDEX,
agentid varchar2(5) not null,
agentname varchar2(25),
carmodel varchar2(25),
mfname varchar2(25))
CREATE SEQUENCE EXCELLENTSALES_SEQ
START WITH 1
INCREMENT BY 1;
create or replace trigger filltable
after insert on salestransaction
for each row
declare
aname varchar2(25);
modname varchar2(25);
manfname varchar2(25);
askpr number;
agrpr number;
begin
SELECT m.NAME, mf.NAME, c.ASKINGPRICE
INTO modname, manfname, askpr
FROM CAR c
INNER JOIN MODEL m
ON m.MODELNO = c.MODELNO
INNER JOIN MANUFACTURER mf
ON mf.MANUFACTURERID = m.MANUFACTURERID
WHERE c.VIN = :NEW.VIN;
SELECT sa.NAME
INTO aname
FROM SALESAGENT sa
WHERE sa.AGENTID = :NEW.AGENTID;
agrpr := :NEW.AGREEDPRICE;
if agrpr > askpr * 1.2 then
insert into excellentsales (EXCELLENTSALES_ID, AGENTID, AGENTNAME, CARMODEL, MFNAME)
values(EXCELLENTSALES_SEQ.nextval, :NEW.AGENTID, aname, modname, manfname);
end if;
end filltable;
I also redesigned your EXCELLENTSALES table to include a primary key which is not the AGENTID. As originally designed EXCELLENTSALES did not record the actual AGENTID (which should apparently be coming from SALESTRANSACTION), which in the real world might be needed, for example, for paying commissions.