I'm trying to create a trigger and a function to update some columns (roles and is_verified) for the first user created. Here is my function :
CREATE OR REPLACE FUNCTION public.first_user()
RETURNS trigger
LANGUAGE plpgsql
AS $function$
DECLARE
begin
if(select count(*) from public.user = 1) then
update new set new.is_verified = true and new.roles = ["ROLE_USER", "ROLE_ADMIN"]
end if;
return new;
end;
$function$
;
and my trigger :
create trigger first_user
before insert
on
public.user for each row execute function first_user()
I'm working on Dbeaver and Dbeaver won't persist my function because of a syntax error near the "=". Any idea ?
Quite a few things are wrong in your trigger function. Here it is revised w/o changing your business logic.
However this will affect the second user, not the first. Probably you shall compare the count to 0. Then the condition shall be if not exists (select from public.user) then
CREATE OR REPLACE FUNCTION public.first_user()
RETURNS trigger LANGUAGE plpgsql AS
$function$
begin
if ((select count(*) from public.user) = 1) then
-- probably if not exists (select from public.user) then
new.is_verified := true;
new.roles := array['ROLE_USER', 'ROLE_ADMIN'];
end if;
return new;
end;
$function$;
Related
Here is my trigger function
CREATE OR REPLACE FUNCTION test_table_insert()
RETURNS TRIGGER
AS $$
BEGIN
IF NEW.id IS NULL THEN
RAISE EXCEPTION 'id is null';
END IF;
UPDATE e_sub_agreement SET ro_id = NEW.id WHERE id = NEW.id;
RETURN NEW;
END;
$$
LANGUAGE plpgsql;
CREATE TRIGGER test_table_insert AFTER INSERT ON e_sub_agreement FOR EACH ROW EXECUTE PROCEDURE test_table_insert();
The problem is that it doesn't update table e_sub_agreement. I checked NEW value and everything is good. It returns with the new id. If I change where statement id = "some existing id in table", then it works. It changes ro_id to the new id. How is it possible? My guess is that data has not been inserted into table and trigger function can't find row with the given id. But it's not how trigger's after insert function works. What's the magic?
An AFTER trigger can not change anything. Running an additional UPDATE is also quite inefficient. Change this to a BEFORE trigger and assign the value you want:
CREATE OR REPLACE FUNCTION test_table_insert()
RETURNS TRIGGER
AS $$
BEGIN
IF NEW.id IS NULL THEN
RAISE EXCEPTION 'id is null';
END IF;
NEW.ro_id := NEW.id;
RETURN NEW;
END;
$$
LANGUAGE plpgsql;
CREATE TRIGGER test_table_insert
BEFORE INSERT ON e_sub_agreement
FOR EACH ROW EXECUTE PROCEDURE test_table_insert();
Note that the NOT NULL check is better done by defining the column as NOT NULL.
I have a task in school which requires me to create a table and a trigger.
I don't really know how to explain it but how can I check if cID is inside the select statement within the trigger function ?
Basically my goal is to only allow cID values which are not inside of "SELECT * from Example2 natural join Example3". Can anyone help me with that? Thank you.
CREATE TABLE Example(
cID INTEGER REFERENCES Example2(attr),
level INTEGER CHECK (level BETWEEN 1 AND 10));
CREATE FUNCTION exp() RETURNS TRIGGER AS
$$
BEGIN
IF EXISTS (select * from Example2 natural join Example3) THEN
RAISE EXCEPTION '...';
END IF;
return null;
END; $$ language plpgsql;
CREATE CONSTRAINT TRIGGER trg
AFTER INSERT OR UPDATE ON Example
FOR EACH ROW
EXECUTE PROCEDURE exp();
CREATE FUNCTION exp() RETURNS TRIGGER AS
$$
BEGIN
IF EXISTS (select 1 from Example2 a where a.cID = new.cID ) THEN
RAISE EXCEPTION '...';
END IF;
return RETURN NEW;
END; $$ language plpgsql;
I have a small table for news. I want to make a trigger which sets the update date and update time in the row (only for the rows that were updated)
I tried making the following:
CREATE FUNCTION add_update_dates()
RETURNS TRIGGER
LANGUAGE plpgsql
AS $$
BEGIN
IF (OLD.news_name IS DISTINCT FROM NEW.news_name OR
OLD.news_description IS DISTINCT FROM NEW.news_description OR
OLD.news_text IS DISTINCT FROM NEW.news_text) THEN
UPDATE news SET news_update_date = current_date, news_update_time = current_time;
END IF;
RETURN new;
END
$$;
CREATE TRIGGER update_news_dates
AFTER UPDATE ON news
FOR EACH ROW
EXECUTE PROCEDURE add_update_dates();
But the trigger updates each row in my table (even those that are not updated), when I want only the updated ones. What am I doing wrong?
Your update statement is updating all the rows in the table! It has no where clause.
Just use assignment:
CREATE FUNCTION add_update_dates()
RETURNS TRIGGER
LANGUAGE plpgsql
AS $$
BEGIN
IF (OLD.news_name IS DISTINCT FROM NEW.news_name OR
OLD.news_description IS DISTINCT FROM NEW.news_description OR
OLD.news_text IS DISTINCT FROM NEW.news_text
) THEN
NEW.news_update_date := current_date;
NEW.news_update_time := current_time;
END IF;
RETURN new;
END;
$$;
As an aside, storing date/time in separate columns makes no sense to me.
I'm working on my first ever Trigger. When I'm doing an INSERT on table I want to conditionaly remove rows from other table.
Here is a trigger:
CREATE OR REPLACE FUNCTION clear_seen_by()
RETURNS trigger AS
$BODY$
BEGIN
IF (OLD.popup = '1') THEN
DELETE FROM news_seen_by;
END IF;
RETURN NULL;
END;
$BODY$
LANGUAGE plpgsql VOLATILE
COST 100;
Invoked by:
CREATE TRIGGER clear_seen_by
AFTER INSERT
ON news
FOR EACH STATEMENT
EXECUTE PROCEDURE clear_seen_by();
As an error I see that NEW or OLD (if I motify the trigger) is not declared/unknown. Where is the problem?
In an INSERT statement you do not have an OLD record defined.
You should use NEW.popup instead, and also declare the trigger to be FOR EACH ROW.
CREATE OR REPLACE FUNCTION clear_seen_by() RETURNS trigger AS
$BODY$
BEGIN
IF (NEW.popup = '1') THEN
DELETE FROM news_seen_by;
END IF;
RETURN NULL;
END;
$BODY$
LANGUAGE plpgsql VOLATILE COST 100;
CREATE TRIGGER
clear_seen_by
AFTER INSERT ON
news
FOR EACH ROW EXECUTE PROCEDURE
clear_seen_by();
You declare a trigger FOR EACH STATEMENT. Maybe you need FOR EACH ROW?
FOR EACH STATEMENT triggers do not have NEW and OLD.
I have a trigger function I'm trying to have execute in Postgres.
It compiles and adds the trigger, however it does not insert the value into the table as I had hoped.
The function it uses looks like this:
CREATE OR REPLACE FUNCTION
calc_gnpDifference(n integer, o integer)
RETURNS NUMERIC AS $$
SELECT $1 ::numeric - $2::numeric AS gnpDifference;
$$ LANGUAGE SQL;
And the Trigger part:
CREATE OR REPLACE FUNCTION autoCalculate() RETURNS TRIGGER AS $$
BEGIN
IF NEW.gnp_old > NEW.gnp_old THEN
NEW.gnpDifference := calc_gnpDifference(NEW.gnp_old, NEW.gnp);
END IF;
RETURN NEW;
END;
$$ LANGUAGE plpgsql;
DROP TRIGGER insertDifference ON country;
CREATE TRIGGER insertDifference BEFORE INSERT ON country
FOR EACH ROW EXECUTE PROCEDURE autoCalculate();
However, when I insert data, the trigger does not update the gnpDifference field as I had hoped. Thoughts on why this might be happening?
Obviously this condition: IF NEW.gnp_old > NEW.gnp_old will never be true so the trigger will never have any effect.