How to assign value from insert statement to variable from a trigger

Question

Hi,
I got this really annoying problem and I don't know if I am doing it correctly.
I have a BEFORE INSERT trigger on a table. When someone executes an insert statement I want to grab the value of a column from that statement and assign it to a variable and then do stuff with it. I'm stuck on the assignment.. look below..
CREATE OR REPLACE TRIGGER CARS.geotest2_trigger
BEFORE INSERT ON CARS.GEO_TEST2
FOR EACH ROW
DECLARE
v_chainkey nchar(32);
v_chainkey2 nchar(32);
not_exists EXCEPTION;
BEGIN
:NEW.CHAINKEY := v_chainkey;
SELECT GEO_TEST.CHAINKEY INTO v_chainkey2 FROM GEO_TEST WHERE GEO_TEST.CHAINKEY = v_chainkey;
IF v_chainkey2 = '' or v_chainkey2 is null THEN
RAISE not_exists;
ELSE
INSERT INTO GEO_TEST2 VALUES(:NEW.CHAINKEY, :NEW.BLA, :NEW.FOO);
END IF;
EXCEPTION
WHEN not_exists THEN
RAISE_APPLICATION_ERROR(-20010, 'Chainkey does not exist in parent table GEO_TEST');
END;
I keep getting this error
Error: ORA-04098: trigger 'CARS.GEOTEST2_TRIGGER' is invalid and failed re-validation
SQLState: 42000
ErrorCode: 4098

Answer 1

It isn't assigning because v_chainkey is not at the left hand side of the assignment statement.
test@ORA10G>
test@ORA10G>
test@ORA10G> declare
  2    x  number := 5;
  3    y  number;
  4  begin
  5    x := y; -- does not assign anything to y; assigns NULL to x,
  6            -- because y is NULL at this point
  7            -- so, essentially the value 5 of x is *LOST* now
  8    dbms_output.put_line('x = '||x);
  9  end;
10  /
x =
PL/SQL procedure successfully completed.
test@ORA10G>
test@ORA10G>
test@ORA10G>In any case, here's what you are probably looking for:
test@ORA10G>
test@ORA10G> --
test@ORA10G> drop table geo_test;
drop table geo_test
ERROR at line 1:
ORA-00942: table or view does not exist
test@ORA10G> drop table geo_test2;
drop table geo_test2
ERROR at line 1:
ORA-00942: table or view does not exist
test@ORA10G>
test@ORA10G> create table geo_test (chainkey nchar(32));
Table created.
test@ORA10G> insert into  geo_test (chainkey) values ('a');
1 row created.
test@ORA10G> insert into  geo_test (chainkey) values ('');
1 row created.
test@ORA10G>
test@ORA10G> create table geo_test2 (chainkey nchar(32), bla number(1), foo number(1));
Table created.
test@ORA10G>
test@ORA10G>
test@ORA10G> CREATE OR REPLACE TRIGGER geotest2_trigger
  2  BEFORE INSERT ON GEO_TEST2
  3  FOR EACH ROW
  4  DECLARE
  5    v_chainkey2  nchar(32);
  6    not_exists   EXCEPTION;
  7  BEGIN
  8    SELECT GEO_TEST.CHAINKEY INTO v_chainkey2 FROM GEO_TEST WHERE nvl(GEO_TEST.CHAINKEY,'~') = nvl(:new.chainkey,'~');
  9    IF v_chainkey2 is null THEN
10      RAISE not_exists;
11    END IF;
12  EXCEPTION
13    WHEN not_exists THEN
14      RAISE_APPLICATION_ERROR(-20010, 'Chainkey does not exist in parent table GEO_TEST');
15  END;
16  /
Trigger created.
test@ORA10G>
test@ORA10G> --
test@ORA10G> insert into geo_test2 (chainkey,bla,foo) values ('b',1,1);
insert into geo_test2 (chainkey,bla,foo) values ('b',1,1)
ERROR at line 1:
ORA-01403: no data found
ORA-06512: at "TEST.GEOTEST2_TRIGGER", line 5
ORA-04088: error during execution of trigger 'TEST.GEOTEST2_TRIGGER'
test@ORA10G>
test@ORA10G> --
test@ORA10G> insert into geo_test2 (chainkey,bla,foo) values (null,1,1);
insert into geo_test2 (chainkey,bla,foo) values (null,1,1)
ERROR at line 1:
ORA-20010: Chainkey does not exist in parent table GEO_TEST
ORA-06512: at "TEST.GEOTEST2_TRIGGER", line 11
ORA-04088: error during execution of trigger 'TEST.GEOTEST2_TRIGGER'
test@ORA10G>
test@ORA10G> --
test@ORA10G> insert into geo_test2 (chainkey,bla,foo) values ('a',1,1);
1 row created.
test@ORA10G>
test@ORA10G>
test@ORA10G>pratz
I think the sole purpose of that "not_exists" exception is this -
If you try to insert a NULL value for GEO_TEST2.CHAINKEY, then this trigger will throw an error even if at least one NULL value exists in GEO_TEST.CHAINKEY column.
Not sure if that's something that you wanted.
Message was edited by:
pratz