Help for a trigger that may have null

Question

hi i am having a trigger for the following table
SQL> desc know_how_page_cfg;
Name Null? Type
CFG_ID NOT NULL NUMBER(11)
WOAD_REF NUMBER(11)
WYCD_REF NUMBER(11)
GLOSSARY_REF NUMBER(11)
TIP_REF NUMBER(11)
WOAD_VPATH VARCHAR2(1024)
WYCD_VPATH VARCHAR2(1024)
GLOSSARY_VPATH VARCHAR2(1024)
TIP_VPATH VARCHAR2(1024)
VPATH NOT NULL VARCHAR2(1024)
INTRO_BLURB NOT NULL VARCHAR2(1024)
and the trigger is
CREATE OR REPLACE TRIGGER INSERTKNOWHOW_REF BEFORE INSERT ON
     know_how_page_cfg FOR EACH ROW
BEGIN
SELECT ASSET_ID into :NEW.WOAD_REF FROM ASSET WHERE VPATH
= :NEW.WOAD_VPATH;
SELECT ASSET_ID into :NEW.WYCD_REF FROM ASSET WHERE VPATH
= :NEW.WYCD_VPATH;
SELECT ASSET_ID into :NEW.GLOSSARY_REF FROM ASSET WHERE VPATH
= :NEW.GLOSSARY_VPATH;
SELECT ASSET_ID into :NEW.TIP_REF FROM ASSET WHERE VPATH
= :NEW.TIP_VPATH;
END;
the trigger is working fine if i am inserting all the values.
as you noticed that they might be null too.if i am not inserting the value of any of the vpaths the trigger is returning the nodata found error.
how can i execute the trigger so that it works though one of the values are not inserted.
please help me.

Answer 1

Hi,
IF the select is not returning any rows and you want to continue then you can put all the SELECT in this block and catch the error and continue.
BEGIN
-- Your selects statments
EXCEPTION WHEN NO_DATA_FOUND THEN
NULL;
END;     -- END OF BLOCK
thanks