Invalid NEW or OLD specification error - sql

Question

I'm trying to create trigger that checks if a phone number if in the (###) ###-#### format, if it this then nothing will happen, if is not then it will be fixed; however if there are more than 10 digits in the number then it will be turned to NULL.
Unfortunately I keep getting the Invalid NEW or OLD specification error in this trigger and I don't know why.
CREATE OR REPLACE TRIGGER phone_correction
BEFORE INSERT OR UPDATE OF vendor_phone
ON vendors
FOR EACH ROW
WHEN (NEW.vendor_phone != REGEXP_LIKE(vendor_phone, '^\(\d{3}\) \d{3}-\d{4}$'))
BEGIN
IF :NEW.vendor_phone != REGEXP_LIKE(vendor_phone, '^\D*(?:\d\D*){10}$')
THEN
:NEW.vendor_phone := null;
DBMS_OUTPUT.PUT_LINE( 'The phone number is bad so setting to null.');
ELSE
:NEW.vendor_phone := REGEXP_LIKE(vendor_phone, '^\(\d{3}\) \d{3}-\d{4}$');
END IF;
END;

Answer 1

There are several errors here; as others have said you need to explicitly use :new. and :old. to reference columns in your trigger, so REGEXP_LIKE(vendor_phone becomes REGEXP_LIKE(:new.vendor_phone.
However, there are some more fundamental errors.
As with the LIKE operator, REGEXP_LIKE() returns a Boolean. Thus, your statement:
IF :NEW.vendor_phone != REGEXP_LIKE(vendor_phone, '^\D*(?:\d\D*){10}$')
is actually IF <string> != <Boolean>, which'll never work.
Using DBMS_OUTPUT in a trigger isn't of any help to you unless you're going to be there to look at whatever logs you're keeping for every row that's been inserted, and then do something to correct whatever issues there are.
Silently removing data is bad practice, if you're going to change something then it's better to raise an error and let the calling code/user decide what to do instead.
If you don't want to let the calling code/user do anything and definitely want to NULL the column if it doesn't conform to a pattern then don't try and insert the data at all.
The ELSE condition in your IF statement is unnecessary, as :new.vendor_phone is already in the correct format.
Personally, I'd completely remove the trigger and add a constraint to check that the format in the column is the one in which you want:
SQL> alter table vendors
2 add constraint chk_vendors_phone
3 check (regexp_like(vendor_phone, '^\(\d{3}\) \d{3}-\d{4}$'));
Then, when trying to insert data it'll be successful if the format is correct and unsuccessful if the format is incorrect:
SQL> insert into vendors (vendor_phone)
2 values ('[phone]');
1 row created.
SQL> insert into vendors (vendor_phone)
2 values ('(123) 123-124');
insert into vendors (vendor_phone)
*
ERROR at line 1:
ORA-02290: check constraint (CHK_VENDORS_PHONE) violated
SQL>
You can then decide what to do with the phones that have errored. As I've stated above, if you definitely want to NULL the incorrectly formatted phones then only insert data which matches this pattern. If anyone touches the code the check constraint will ensure that the data is still in the correct format.
If you absolutely must use a trigger, then it can be simplified to something like the following:
create or replace trigger phone_correction
before insert or update of vendor_phone
on vendors
for each row
when (not regexp_like(new.vendor_phone, '^\(\d{3}\) \d{3}-\d{4}$'))
begin
:new.vendor_phone := null;
end;
This checks to see (using Boolean logic) whether the result of the REGEXP_LIKE() function is false. If it is, then it NULLs the phone. Here's an example of it working:
SQL> create table vendors (id number, vendor_phone varchar2(100));
Table created.
SQL> create trigger phone_correction
2 before insert or update of vendor_phone
3 on vendors
4 for each row
5 when (not regexp_like(new.vendor_phone, '^\(\d{3}\) \d{3}-\d{4}$'))
6 begin
7 :new.vendor_phone := null;
8 end;
9 /
Trigger created.
SQL> insert into vendors
2 values (1, '[phone]');
1 row created.
SQL> insert into vendors
2 values (2, '(123) 123-124');
1 row created.
SQL> select * from vendors;
ID VENDOR_PHONE
---------- --------------------
1 [phone]
2
SQL>
... instead of setting a phone number to null :new.vendor_phone := null; how would you make so it can automatically modify the phone number into the correct format? (###) ###-####
This is actually the example in the documentation for REGEXP_REPLACE(). To make this more extensible, I'd remove all non-numeric characters from the string and then attempt the transformation. In order to remove the non-numeric characters:
regexp_replace(vendor_phone, '[^[:digit:]]')
This means replace everything that's not in the character class [:digit:] with nothing. Then, to transform you can use sub-expressions as described in the documentation:
regexp_replace(regexp_replace(vendor_phone, '[^[:digit:]]')
, '^([[:digit:]]{3})([[:digit:]]{3})([[:digit:]]{4})$'
, '(\1) \2-\3')
This looks for 3 ({3}) digits twice and then 4 digits, splitting them into sub-expressions and then putting them in the correct format. There are many ways to do this, and this may not be the quickest, but it makes your intention most clear.
I would not do this in a trigger, do this when you insert into the table instead. Better, and if this is a client-side application, you should be ensuring that your numbers are in the correct format before you hit the database at all.

Answer 2

You have to specify the :NEW whenever you are using the column names. try this:
CREATE OR REPLACE TRIGGER phone_correction
BEFORE INSERT OR UPDATE OF vendor_phone
ON vendors
FOR EACH ROW
WHEN (NEW.vendor_phone != REGEXP_LIKE(NEW.vendor_phone, '^\(\d{3}\) \d{3}-\d{4}$'))
BEGIN
IF :NEW.vendor_phone != REGEXP_LIKE(:NEW.vendor_phone, '^\D*(?:\d\D*){10}$')
THEN
:NEW.vendor_phone := null;
DBMS_OUTPUT.PUT_LINE( 'The phone number is bad so setting to null.');
ELSE
:NEW.vendor_phone := REGEXP_LIKE(:NEW.vendor_phone, '^\(\d{3}\) \d{3}-\d{4}$');
END IF;
END;

Answer 3

You must specify the keywords NEW and OLD preceded by a colon (:) everywhere you are referring to the columns.
The only exception to this rule is the WHEN clause.
The NEW and OLD keywords, when specified in the WHEN clause, are not
considered bind variables, so are not preceded by a colon (:).
However, you must precede NEW and OLD with a colon in all references
other than the WHEN clause.
So, in your code, you must refer the new values in the conditions as :NEW.
REGEXP_LIKE(vendor_phone
Should be,
REGEXP_LIKE(:NEW.vendor_phone