Delete row that have fk

[sk8ergirl]

I have two tables

Student
S_ID      PK
S_NAME

COURSE 
C_ID   PK
C_NAME
S_ID   FK

I've created trigger for both S_ID and C_ID (to generate id no insert update delete before each row )
when I do this

DELETE FROM STUDENT WHERE S_ID = 1

I get this

ORA-04084: cannot change NEW values for this trigger type
ORA-04088: error during execution of trigger 'myTables.S_ID_TRIGGER'

[pritaeas]

What does your trigger do? Doesn't it just need to run on an INSERT?

[sk8ergirl]

trigger is fiered when I insert delete or update it add unique id no