need help with trigger

[Bronte1226]

I am trying to create a trigger involving 2 tables.
If a record is updated or inserted, after the insert I need to update a field in another table. For example if in the first table there is an inserted row then i need the field in the other table to be updated to a particular text string where the id fields that reference each other are equal (for each row) if the field is updated then i need to change the field in the other table to a different string (where the id's are equal again) I have something like this but it isn't working. I think that i am using the if then else statement incorrectly.

CREATE OR REPLACE TRIGGER BOOKS_TRG AFTER INSERT OR
UPDATE OF LEVEL ON BOOKS FOR EACH ROW BEGIN
UPDATE CLIENT
IF CLIENT_BOOK = 'L'
THEN SET CLIENT_BOOK = 'U'
ELSE SET CLIENT_BOOK = 'U'
WHERE CLIENT.CLIENT_ID = BOOKS.CLIENT_ID
END IF;
END;
/

I am new to triggers so I feel lost. Help!

 

[Mockenrue]

In triggers you must refer to a column like:
:new.<column_name>
or:
ld.<column_name>

And you can use 'if inserting' and 'if updating'.

So you can construct something like:

begin

if inserting then

if :new.client_book = 'L'
then
update client
set book = ...
where client_id = :new.client_id;
else
update client
set book = ...
where client_id = :new.client_id;
end if;

elsif updating then

...
...
...

end if;

end;
/