oracle - insert trigger in pl/sql -

i cant find right structure following question in pl/sql: need trigger on “products table” check price before inserting new product, product price must not exceed 4000$.

create or replace trigger pro  before update of price  on products each row  declare  pr products.price%type; begin  if pr < 4000  insert products values (:old.product_id,:old.price); end if;  end; 

please help

use check constraint instead of trigger:

create table products (price number);  alter table products add constraint check_price check (price < 4000); 

test:

insert products values (5000)  => error 

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edit: if insist on trigger version:

create or replace trigger pro before insert or update of price on products  each row  begin  if :new.price > 4000    raise_application_error(-20101, 'price exceeds 4000.'); end if;  end;