SQL Loader and INSERT Trigger

Question

I have problem and your help to solve it would be very much appreciated.
I am uploading a text file with SQL Loader into a table. Since I used APPEND option in the Loader, I don't want records to be duplicated. So, I wrote a "BEFORE INSERT .. FOR EACH ROW" trigger to check whether that row already exists or not.
For example, let us consider a table TEST as follows.
Fld1     NUMBER(2);
Fld2     VARCHAR2(10);
Fld3     VARCHAR2(10);
I have a trigger on this table.
CREATE OR REPLACE TRIGGER Trg_Bef_Insert_Test
BEFORE INSERT ON Test FOR EACH ROW
DECLARE
vCount NUMBER(2);
DuplicateRow EXCEPTION;
BEGIN
SELECT Count(*) INTO vCount FROM Test
     WHERE fld1 || fld2 || fld3 = :new.fld1 || :new.fld2 || :new.fld3;
IF vCount > 0 THEN
     RAISE DuplicateRow;
END IF;
EXCEPTION
WHEN DuplicateRow THEN
     Raise_Application_Error (-20001,'Record already exists');
WHEN OTHERS THEN
     DBMS_OUTPUT.PUT_LINE('ERROR : ' || SQLCODE || '; ' || SUBSTR(SQLERRM, 1, 150));
END;
Please refer to the following SQL statements which I executed in the SQL Plus.
SQL> insert into test values (1,'one','first');
1 row created.
SQL> insert into test values (1,'one','first');
insert into test values (1,'one','first')
ERROR at line 1:
ORA-20001: Record already exists
ORA-06512: at "CAMELLIA.TRG_TEST", line 13
ORA-04088: error during execution of trigger 'CAMELLIA.TRG_TEST'
Would anyone tell me why do errors -6512 and -4088 occur ?
Also, if you have any other suggestion to handle this situation, please let me know.
By the way, I am using Oracle 8.1.7.
Thank you.

Answer 1

There are a few things wrong here, but you should really use a unique constraint for this.
SQL> create table t (a number, b number, c number,
  2      constraint uk unique (a, b, c));
Table created.Here's an example data file with 12 records three of which are duplicates.
1,2,3
3,4,5
6,7,8
3,2,1
5,5,5
3,4,5
3,2,1
1,1,1
2,2,2
6,7,8
8,8,8
9,9,9And a control file
load data
infile 'in.dat'
append
into table t
fields terminated by ',' optionally enclosed by '"'
(a, b, c)Running it with sql loader, inserts the nine records, outputs the three duplicates to a .bad file and logs all the errors in the .log file. No need for triggers or any code.
$ sqlldr control=in.ctl
Username:xxx
Password:
SQL*Loader: Release 9.2.0.1.0 - Production on Mon Apr 21 23:16:44 2003
Copyright (c) 1982, 2002, Oracle Corporation.  All rights reserved.
Commit point reached - logical record count 12
$ cat in.bad
3,4,5
3,2,1
6,7,8
SQL> select * from t;
         A          B          C
         1          2          3
         3          4          5
         6          7          8
         3          2          1
         5          5          5
         1          1          1
         2          2          2
         8          8          8
         9          9          9
9 rows selected.