Order of precedence for validation of a column in a table ?

Question

Can anybody tell me order of precedence for validation of a column in a table
Which one will get executed first ?
Integrity constraint or Database trigger.

Answer 1

Why cant you test it..?
SQL> create table test_1
  2  (c1 number references emp);
Table created.
SQL> create or replace trigger trig_1
  2  before insert on test_1
  3  for each row
  4  begin
  5  if :new.c1 < 1 then
  6   raise_application_error(-20000,'Invalid value');
  7  end if;
  8  end;
  9  /
Trigger created.
SQL> insert into test_1
  2  values(0);
insert into test_1
ERROR at line 1:
ORA-20000: Invalid value
ORA-06512: at "SCOTT.TRIG_1", line 3
ORA-04088: error during execution of trigger 'SCOTT.TRIG_1'
SQL> create or replace trigger trig_1
  2  after insert on test_1
  3  for each row
  4  begin
  5  if :new.c1 < 1 then
  6   raise_application_error(-20000,'Invalid value');
  7  end if;
  8  end;
  9  /
Trigger created.
SQL> insert into test_1
  2  values(0);
insert into test_1
ERROR at line 1:
ORA-20000: Invalid value
ORA-06512: at "SCOTT.TRIG_1", line 3
ORA-04088: error during execution of trigger 'SCOTT.TRIG_1'
SQL> drop trigger trig_1;
Trigger dropped.
SQL> insert into test_1
  2  values(0);
insert into test_1
ERROR at line 1:
ORA-02291: integrity constraint (SCOTT.SYS_C005925) violated - parent key not
found