I have this view
CREATE VIEW NaveTiconderoga AS
SELECT nume, tip, cate_arme, diametru_tun, deplasament, Nave.clasa, anul_lansarii
FROM Clase, Nave
WHERE Clase.clasa = Nave.Clasa AND Nave.Clasa = 'Ticonderoga';
I wish to create a trigger to allow inserting through this view.
I wrote the following code, but i'm sure that it isn't correct as far as the WHERE clause from the SELECT.
Any pointers please?
CREATE OR REPLACE TRIGGER ticonderoga
instead of insert on NaveTiconderoga
referencing new as new old as old
begin
insert into clase (clasa, tip, cate_arme, diametru_tun, deplasament)
values (:new.clasa, :new.tip, :new.cate_arme, :new.diametru_tun, :new.deplasament);
insert into nave (nume, clasa, anul_lansarii)
values (:new.nume, :new.clasa, :new.anul_lansarii);
end;
If you want to restrict the value inserted into the view (and thus the underlying tables), so you can't put in something that the view itself won't show, you can't use a check constraint; but you can test the value inside the trigger and throw an exception if you see something you don't like:
CREATE OR REPLACE TRIGGER ticonderoga
instead of insert on NaveTiconderoga
referencing new as new old as old
begin
if :new.clasa is null or :new.clasa != 'Ticonderoga' then
raise_application_error(-20001, 'Invalid clasa');
end if;
insert into clase (clasa, tip, cate_arme, diametru_tun, deplasament)
...
SQL Fiddle of what I think you're worried about. If you change the trigger in that to:
create trigger tr42
instead of insert on v42
begin
if :new.id != 1 then
raise_application_error(-20001, 'Invalid ID');
end if;
insert into t42 (id) values (:new.id);
end;
/
... then the second insert will fail. I think that is what you want to happen, anyway.
Related
I've found few questions addressing the same question but without a better solution.
I need to create an Oracle trigger which will prevent new inserts upon a condition, but silently (without raising an error).
Ex : I need to stop inserting rows with bar='FOO' only. (I can't edit the constraints of the table, can't access the procedure which really does the insertion etc so the trigger is the only option)
Solutions so far confirms that it isn't possible. One promising suggestion was to create an intermediate table, insert key values to that when bar='FOO' and then delete those records from original table once insertion is done, which is not correct I guess.
Any answer will be highly appreciated.
Apparently, it is not possible to use a trigger to stop inserts without raising an exception.
However, if you have access to the schema (and asking about a trigger this is probably ok), you could think about replacing the table with a view and an instead of trigger.
As a minimal mock up for your current table. myrole is just a stand in for the privileges granted on the table:
CREATE ROLE myrole;
CREATE TABLE mytable (
bar VARCHAR2(30)
);
GRANT ALL ON mytable TO myrole;
Now you rename the table and make sure nobody can directly access it anymore, and replace it with a view. This view can be protected by a instead of trigger:
REVOKE ALL ON mytable FROM myrole;
RENAME mytable TO myrealtable;
CREATE OR REPLACE VIEW mytable AS SELECT * FROM myrealtable;
GRANT ALL ON mytable TO myrole;
CREATE OR REPLACE TRIGGER myioftrigger
INSTEAD OF INSERT ON mytable
FOR EACH ROW
BEGIN
IF :new.bar = 'FOO' THEN
NULL;
ELSE
INSERT INTO myrealtable(bar) VALUES (:new.bar);
END IF;
END;
/
So, if somebody is inserting a normal row into the fake view, the data gets inserted into your real table:
INSERT INTO mytable(bar) VALUES('OK');
1 row inserted.
SELECT * FROM mytable;
OK
But if somebody is inserting the magic value 'FOO', the trigger silently swallows it and nothing gets changed in the real table:
INSERT INTO mytable(bar) VALUES('FOO');
1 row inserted.
SELECT * FROM mytable;
OK
Caution: If you want to protect your table from UPDATEs as well, you'd have to add a second trigger for the updates.
One way would be to hide the row. From 12c this is reasonably easy:
create table demo
( id integer primary key
, bar varchar2(10) );
-- This adds a hidden column and registers the table for in-database archiving:
alter table demo row archival;
-- Set the hidden column to '1' when BAR='FOO', else '0':
create or replace trigger demo_hide_foo_trg
before insert or update on demo
for each row
begin
if :new.bar = 'FOO' then
:new.ora_archive_state := '1';
else
:new.ora_archive_state := '0';
end if;
end demo_hide_foo_trg;
/
-- Enable in-database archiving for the session
-- (probably you could set this in a log-on trigger):
alter session set row archival visibility = active;
insert into demo (id, bar) values (1, 'ABC');
insert into demo (id, bar) values (2, 'FOO');
insert into demo (id, bar) values (3, 'XYZ');
commit;
select * from demo;
ID BAR
-------- --------
1 ABC
3 XYZ
-- If you want to see all rows (e.g. to delete hidden rows):
alter session set row archival visibility = all;
In earlier versions of Oracle, you could achieve the same thing using a security policy.
Another way might be to add a 'required' flag which defaults to 'Y' and set it to to 'N' in a trigger when bar = 'FOO', and (assuming you can't change the application to use a view etc) have a second trigger delete all such rows (or perhaps better, move them to an archive table).
create table demo
( id integer primary key
, bar varchar2(10) );
alter table demo add required_yn varchar2(1) default on null 'Y';
create or replace trigger demo_set_not_required_trg
before insert or update on demo
for each row
begin
if :new.bar = 'FOO' then
:new.required_yn := 'N';
end if;
end demo_hide_foo_trg;
/
create or replace trigger demo_delete_not_required_trg
after insert or update on demo
begin
delete demo where required_yn = 'N';
end demo_delete_not_required_trg;
/
I have a ruby app. The app is doing the insert,update and delete on a particular table.
It does 2 kinds of INSERT, one insert should insert a record in the table and also into trigger_logs table. Another insert is just to insert the record into the table and do nothing. Another way to put it is, one kind of insert should log that the 'insert' happened into another table and another kind of insert should just be a normal insert. Similarly, there are 2 kinds of UPDATE and DELETE also.
I have achieved the 2 types of INSERT and UPDATE using a trigger_disable. Please refer to the trigger code below.
So, when I do a INSERT, I will set the trigger_disable boolean to true if I don't want to log the trigger. Similarly I am doing for an UPDATE too.
But I am not able to differentiate between the 2 kinds of DELETE as I do for an INSERT or UPDATE. The DELETE action is logged for both kinds of DELETE.
NOTE: I am logging all the changes that are made under a certain condition, which will be determined by the ruby app. If the condition is not satisfied, I just need to do a normal INSERT, UPDATE or DELETE accordingly.
CREATE OR REPLACE FUNCTION notify_#{#table_name}()
RETURNS TRIGGER
LANGUAGE plpgsql
AS $$
DECLARE
changed_row_id varchar(100);
BEGIN
IF TG_OP = 'DELETE' THEN
-- When the trigger is due to a delete
IF (OLD.trigger_disable IS NULL)
OR (OLD.trigger_disable = false) THEN
-- Prevent the trigger if trigger_disable is 'true'
-- The Problem is here: This insertion into the
-- trigger_logs table happens
-- for all the delete statements.
-- But during certain deletes I should not
-- insert into trigger_logs
INSERT INTO trigger_logs (table_name, action, row_id, dirty)
VALUES (
'#{#table_name}',
CAST(TG_OP AS Text),
OLD.id,
true
) RETURNING id into changed_row_id;
END IF;
RETURN OLD;
ELSE
-- The trigger is due to a Insert or Update
IF (NEW.trigger_disable IS NULL)
OR (NEW.trigger_disable = false) THEN
-- Prevent the trigger if trigger_disable is 'true'
INSERT INTO trigger_logs (table_name, action, row_id, dirty)
VALUES (
'#{#table_name}',
CAST(TG_OP AS Text),
NEW.id,
true
) RETURNING id into changed_row_id;
ELSE
NEW.trigger_disable := false;
END IF;
RETURN NEW;
END IF;
END
I'm going to take a stab in the dark here and guess that you're trying to contextually control whether triggers get fired.
If so, perhaps you can use a session variable?
BEGIN;
SET LOCAL myapp.fire_trigger = 'false';
DELETE FROM ...;
COMMIT;
and in your trigger, test it:
IF current_setting('myapp.fire_trigger') = 'true' THEN
Note, however, that if the setting is missing from a session you won't get NULL, you'll get an error:
regress=> SELECT current_setting('myapp.xx');
ERROR: unrecognized configuration parameter "myapp.xx"
so you'll want to:
ALTER DATABASE mydb SET myapp.fire_trigger = 'true';
Also note that the parameter is text not boolean.
Finally, there's no security on session variables. So it's not useful for security audit, since anybody can come along and just SET myapp.fire_trigger = 'false'.
(If this doesn't meet your needs, you might want to re-think whether you should be doing this with triggers at all, rather than at the application level).
Trying to create an Oracle trigger that runs after a table is updated in any way. I've been googling this all morning and came up with this:
CREATE OR REPLACE TRIGGER gb_qty_change
AFTER UPDATE OR INSERT OR DELETE ON F_ITEM_STORE
FOR EACH ROW
DECLARE
v_qty V_AD_ON_HAND%rowtype;
v_isbn TD_ITEM_DESCRIPTION.TD_IDENTIFIER%type;
BEGIN
delete from gb_transaction where gb_tide = :new.ITST_ITEM_TIDE_CODE;
select TD_IDENTIFIER INTO v_isbn from TD_ITEM_DESCRIPTION where TD_TIDE = :new.ITST_ITEM_TIDE_CODE;
select * INTO v_qty from V_AD_ON_HAND where ITST_ITEM_TIDE_CODE = :new.ITST_ITEM_TIDE_CODE;
insert into gb_transaction(gb_tide, gb_isbn, gb_used_on_hand, gb_new_on_hand)
values(:new.ITST_ITEM_TIDE_CODE, v_isbn, v_qty.USED_ON_HAND, v_qty.NEW_ON_HAND);
END;
/
I'm trying to keep it to a single record per TIDE_CODE in the new table.
V_AD_ON_HAND is a view that pulls an inventory count.
gb_transaction is my new table where I'm logging these events
Comparing it to other peoples code it looks like it should run but I'm getting "Warning: Trigger created with compilation errors."
The problem, I believe is with the :new designations for a delete trigger. There is, after all, no NEW value as the record is expunged. You can only access the :OLD values on delete.
if you section the trigger by operation, you can do this.
CREATE OR REPLACE TRIGGER gb_qty_change
AFTER UPDATE OR INSERT OR DELETE ON F_ITEM_STORE
FOR EACH ROW
DECLARE
v_qty V_AD_ON_HAND%rowtype;
v_isbn TD_ITEM_DESCRIPTION.TD_IDENTIFIER%type;
BEGIN
IF INSERTING or UPDATING then
... insert your existing code
ELSE
... do something similar with the :old values for the deleting case
end if;
END;
/
Incidentally, it is generally helpfull if you tell us WHAT the error is, not just that you had one. If compiling via SQL*Plus script, after the forward slash call to compile the trigger after the "end;" statement, add a line that says:
SHOW ERRORS TRIGGER YOUR_TRIGGER_NAME;
I got this trigger, I want to evaluate the mobile phone and insert into another table if the regexp returns a value. I've tried with this but not success.
delimiter //
create trigger companyA_phones after insert on customer
for each row
begin
set #phone = (select new.phone from customer where new.phone regexp '^0416');
if (#phone) then
insert into company_A(new.id, #phone);
end if;
end//
You don't make it entirely clear what trouble you are having, but I don't think you need to be selecting the .new values like that -- as they are already available to you. Try something like this:
CREATE TRIGGER companyA_phones
AFTER INSERT ON customer
FOR EACH ROW
BEGIN
IF (new.phone REGEXP '^0416' AND new.id IS NOT NULL) THEN
INSERT INTO company_A (customerid, phone)
VALUES (new.id, new.phone);
END IF;
END
The need for this trigger does seem to suggest that your underlying schema design is not correctly normalised, so you might want to think about that too.
I have two Tables.
I want to insert the same record on both tables at the same time.
I.e., while I insert a record for the first table, this same record also is inserted in the second table using a trigger.
Do you have any experience/advice in this process ?
if you're using stored procedures you can easily manage this
CREATE PROCEDURE sp_Insert
#Value varchar(10)
AS
insert into table1 (...,...) values (#value,...)
insert into table2 (...,...) values (#value,...)
I would suggest using Erik's method over a trigger. Triggers tend to cause performance issues, and a lot of times, you forget that the trigger exists, and get unexpected behavior. If you do want to use a trigger however, it will work. here is an example:
CREATE TRIGGER trgTest ON Test
FOR INSERT
AS
INSERT Test2
(Id, value)
SELECT Id, Value
FROM Inserted
Can Use Cursor Concept!
CREATE OR REPLACE TRIGGER bi_order
BEFORE INSERT
ON ord
REFERENCING OLD AS OLD NEW AS NEW
FOR EACH ROW
WHEN (NEW.payment_type = 'CREDIT')
DECLARE
CURSOR cur_check_customer IS
SELECT 'x'
FROM customer
WHERE customer_id = :NEW.customer_id
AND credit_rating = 'POOR';
lv_temp_txt VARCHAR2(1);
lv_poor_credit_excep EXCEPTION;
BEGIN
OPEN cur_check_customer;
FETCH cur_check_customer INTO lv_temp_txt;
IF (cur_check_customer%FOUND) THEN
CLOSE cur_check_customer;
RAISE lv_poor_credit_excep;
ELSE
CLOSE cur_check_customer;
END IF;
EXCEPTION
WHEN lv_poor_credit_excep THEN
RAISE_APPLICATION_ERROR(-20111, 'Cannot process CREDIT ' ||
'order for a customer with a POOR credit rating.');
WHEN OTHERS THEN
RAISE_APPLICATION_ERROR(-20122, 'Unhandled error occurred in' ||
' BI_ORDER trigger for order#:' || TO_CHAR(:NEW.ORDER_ID));
END bi_order;