How does line numbering work in an Oracle trigger?

Question

I have a trigger that's throwing an error, and I am not sure how to know which line of PL/SQL code is throwing that error. My error is

[Oracle]ORA-01403: no data found ORA-06512: at "MYSCHEMA.FOO_BI", line 9

My trigger is something like this:

create or replace TRIGGER "MYSCHEMA"."FOO_BI" 
BEFORE INSERT ON FOO REFERENCING OLD AS OLD NEW AS NEW FOR EACH ROW
DECLARE
 NUM1 NUMBER;
 NUM2 NUMBER;

BEGIN

     -- some comment
  if :new.batch_num is null then
   SELECT COUNT(*) INTO :NEW.BATCH_NUM FROM FOO WHERE CORP_ID = :NEW.CORP_ID;
  end if;

  if :new.batch_id is null or :new.batch_id = '' then
    :NEW.BATCH_ID := :NEW.CORP_ID || '-' || :NEW.BATCH_NUM;
  end if;

/* etc... */     

I found what looks like a similar question but the line numbering starts with the create or replace... and represents my error line as a comment, which I think must be bogus. How is the line numbering reported when an error is thrown in execution of a trigger?

Answer 1

The line numbers refer to the stored source in the Oracle data dictionary. You can determine the actual line numbering by checking the data dictionary views.

SELECT text
  FROM all_source
  WHERE owner = 'MYSCHEMA'
    AND name = 'FOO_BI'
    AND type = 'TRIGGER'
    AND line = 9;

Answer 2

The line numbering (as reported in stack traces) starts with the DECLARE being line 1. So, if you do the following:

CREATE OR REPLACE TRIGGER foo
BEFORE INSERT ON test1 
REFERENCING OLD AS OLD NEW AS NEW 
FOR EACH ROW
DECLARE
n1 NUMBER := 1;
n2 NUMBER := 2;

BEGIN

  -- a comment
  IF :new.n1 IS NULL THEN
    n1 := n2/0;
  END IF;
END;
/

SQL> insert into test1 values (3,'XX','YY',NULL);

insert into test1 values (3,'XX','YY',NULL)

ORA-01476: divisor is equal to zero
ORA-06512: at "XXX.FOO", line 9
ORA-04088: error during execution of trigger 'XXX.FOO'

SQL> select line, text from all_source where name = 'FOO';

      LINE TEXT
---------- --------------------------------------------------------------------------------
         1 TRIGGER foo
         2 BEFORE INSERT ON test1
         3 REFERENCING OLD AS OLD NEW AS NEW
         4 FOR EACH ROW
         5 DECLARE
         6 n1 NUMBER := 1;
         7 n2 NUMBER := 2;
         8 
         9 BEGIN
        10 
        11   -- a comment
        12   IF :new.n1 IS NULL THEN
        13     n1 := n2/0;
        14   END IF;
        15 END;

15 rows selected

You can see the error was reported as happening at line 9, which is actually line 13 in the source.