I created trigger and function.
CREATE TRIGGER trigger_update_quantity AFTER INSERT ON orderitem
FOR EACH ROW EXECUTE PROCEDURE update_quantity();
CREATE OR REPLACE FUNCTION update_quantity() RETURNS TRIGGER AS $quantity_update$
DECLARE
flower INT;
BEGIN
flower = New.flower_num;
UPDATE product SET quantity = quantity - New.quantity
WHERE flower_num = flower;
END;
$quantity_update$
LANGUAGE plpgsql;
When I try to insert a row into a table. Everything i have the following error.
INSERT INTO "public"."orderitem" ("order_num", "flower_num", "quantity", "total_price") VALUES (?, ?, ?, ?);
[2F005] ERROR: control reached end of trigger procedure without RETURN
Where: PL/pgSQL function update_quantity()
Here's what I would write (not tested):
CREATE OR REPLACE FUNCTION update_quantity() RETURNS TRIGGER AS $quantity_update$
DECLARE
flower INT;
BEGIN
flower = New.flower_num;
UPDATE product SET quantity = quantity - New.quantity
WHERE flower_num = flower;
RETURN NEW;
END;
$quantity_update$
LANGUAGE plpgsql;
CREATE TRIGGER trigger_update_quantity AFTER INSERT ON orderitem
FOR EACH ROW EXECUTE PROCEDURE update_quantity();
how is AFTER TRIGGER, you can return RETURN OLD; or RETURN NULL;
Related
I am new to using postgresql, I am trying to make a trigger that just inserts in the Employee table and also inserts in the Vacations table, but I don't know how to assign the values, I do it like that in sql but here I really don't know how
CREATE FUNCTION SP_InsertaVacacionesEmpleado() RETURNS TRIGGER
AS
$$
DECLARE _NumeroIdentificacion INTEGER;
DECLARE _FechaEntrada DATE;
BEGIN
SET _NumeroIdentificacion = SELECT NEW.NumeroIdentificacion FROM "Empleado"
SET _FechaEntrada = SELECT NEW.FechaEntrada FROM "Empleado"
INSERT INTO Vacaciones VALUES(_NumeroIdentificacion, _FechaEntrada, '', 0);
RETURN NEW;
END
$$
LANGUAGE plpgsql
As documented in the manual assignment is done using the := operator, e.g.:
some_variable := 42;
However to assign one or more variables from the result of a query, use select into, e.g.:
DECLARE
var_1 INTEGER;
var_2 DATE;
BEGIN
select col1, col2
into var_1, var_2
from some_table
...
However neither of that is necessary in a trigger as you can simply use the reference to the NEW record directly in the INSERT statement:
CREATE FUNCTION sp_insertavacacionesempleado()
RETURNS TRIGGER
AS
$$
BEGIN
INSERT INTO Vacaciones (...)
VALUES (NEW.NumeroIdentificacion, NEW.FechaEntrada , '', 0);
RETURN NEW;
END
$$
LANGUAGE plpgsql;
Note that you need to define a row level trigger for this to work:
create trigger ..
before insert on ...
for each row --<< important!
execute procedure sp_insertavacacionesempleado() ;
I wan't to add a trigger in a PostgreSQL database. This trigger is used to concatenate values of 2 columns to update a 3rd one. I wan't to run it when a row is inserted or updated in the table.
Table
CREATE TABLE IF NOT EXISTS FILE(ID INT NOT NULL PRIMARY KEY, FOLDER TEXT, NAME TEXT, URL TEXT);
Function
CREATE OR REPLACE FUNCTION LINK() RETURNS trigger AS
$$
BEGIN
IF (TG_OP = 'UPDATE') THEN
UPDATE FILE
SET URL = CONCAT(FOLDER, NAME)
WHERE ID = OLD.ID;
ELSIF (TG_OP = 'INSERT') THEN
UPDATE FILE
SET URL = CONCAT(FOLDER, NAME)
WHERE ID = NEW.ID;
END IF;
RETURN NULL;
END
$$
LANGUAGE PLPGSQL;
Trigger
CREATE TRIGGER TRIGGER_LINK
BEFORE INSERT OR UPDATE
ON FILE
FOR EACH ROW
EXECUTE PROCEDURE LINK();
When I insert a value in table like
INSERT INTO FILE VALUES (1, 'C:\', 'doc.pdf');
I have an error message list index out of range because ID number is not yet created and UPDATE query on INSERT can't execute. But if I make an AFTER UPDATE it will run infinitely.
How to run a trigger function on INSERT or UPDATE with a WHERE clause on ID to target only inserted or updated row ? I'm using PostgreSQL 10.14.
Don't use UPDATE to do that. Just assign the value. Also, a BEFORE trigger should not return null because that will abort the operation.
CREATE OR REPLACE FUNCTION LINK() RETURNS trigger AS
$$
BEGIN
new.url := CONCAT(new.FOLDER, new.NAME);
RETURN new; --<< important!
END
$$
LANGUAGE PLPGSQL;
I've problem with a trigger function in postgresql.
Here my simple code.
CREATE TABLE specie
(specie_id INT PRIMARY KEY GENERATED BY DEFAULT AS IDENTITY,
nome_comune TEXT UNIQUE,
nome_scientifico TEXT UNIQUE);
CREATE TABLE rilevatore
(rilevatore_id INT PRIMARY KEY GENERATED BY DEFAULT AS IDENTITY,
nome_cognome TEXT);
CREATE TABLE evento_investimento
(evento_id INT PRIMARY KEY GENERATED BY DEFAULT AS IDENTITY,
data DATE,
ora TIME WITHOUT TIME ZONE,
rilevatore_id INT REFERENCES rilevatore (rilevatore_id),
specie_id INT REFERENCES specie(specie_id));
CREATE VIEW inserimento_dati_vista AS
SELECT row_number() OVER ()::integer AS gid,
evento_investimento.ora,
evento_investimento.data,
rilevatore.nome_cognome,
specie.nome_comune,
specie.nome_scientifico
FROM evento_investimento
JOIN specie ON evento_investimento.specie_id = specie.specie_id
JOIN rilevatore ON evento_investimento.rilevatore_id = rilevatore.rilevatore_id;
CREATE OR REPLACE FUNCTION inserimento_dati_fun_2() RETURNS trigger AS $$
BEGIN
if not exists(select * from rilevatore where rilevatore.nome_cognome=new.nome_cognome) then
INSERT INTO rilevatore (nome_cognome)
VALUES (NEW.nome_cognome);
end if;
if not exists(select * from specie where specie.nome_comune=new.nome_comune) then
INSERT INTO specie (nome_comune, nome_scientifico)
VALUES (NEW.nome_comune, NEW.nome_scientifico);
end if;
INSERT INTO evento_investimento (data, ora, rilevatore_id, specie_id)
VALUES (NEW.data,NEW.ora,
(SELECT rilevatore_id FROM rilevatore WHERE rilevatore.nome_cognome = NEW.nome_cognome),
(SELECT specie_id FROM specie WHERE specie.nome_comune = NEW.nome_comune));
RETURN NEW;
END;
$$ LANGUAGE plpgsql;
create trigger inserimento_dati_fun_trg
instead of insert on inserimento_dati_vista for each row EXECUTE procedure inserimento_dati_fun_2();
Now, I want to add a function that allow to update all the tables by using the view inserimento_dati_vista.
I've tried with a simple code to update only the data column
CREATE OR REPLACE FUNCTION update_dati_fun_2() RETURNS TRIGGER AS $$
BEGIN
IF (TG_OP = 'UPDATE') THEN
IF old.data is distinct from new.data then
UPDATE evento_investimento
SET data = new.data;
END IF;
END IF;
RETURN NEW;
END;
$$ LANGUAGE plpgsql;
create trigger update_dati_fun_2_trg
instead of update on inserimento_dati_vista for each row EXECUTE procedure update_dati_fun_2();
However when I perfomr the query in order to update only a row, the trigger update all the rows in the table. Here some code to fill data.
INSERT INTO inserimento_dati_vista
(data, ora, nome_cognome, nome_comune, nome_scientifico)
VALUES
('2020-01-01', '16:54:00','mario', 'lupo', 'Canis lupus'),
('2020-01-02', '13:54:00','luca', 'lontra', 'Lutra lutra');
UPDATE inserimento_dati_vista
SET data = '2021-01-02' where nome_cognome = 'luca'
Update function is:
CREATE OR REPLACE FUNCTION update_dati_fun_2() RETURNS TRIGGER AS $$
BEGIN
IF (TG_OP = 'UPDATE') THEN
IF old.data is distinct from new.data then
UPDATE evento_investimento e
SET data = new.data
FROM rilevatore r
WHERE nome_cognome = new.nome_cognome AND r.rilevatore_id = e.rilevatore_id;
END IF;
END IF;
RETURN NEW;
END;
$$ LANGUAGE plpgsql;
I want to update the record of a particular user only. But the update trigger fires for all the users.
CREATE OR REPLACE FUNCTION replace_empty_username_with_null() RETURNS TRIGGER
LANGUAGE plpgsql AS
BEGIN
UPDATE user_temp
SET username=null
WHERE NEW.id = OLD.id and NEW.username = '';
RETURN NEW;
END
CREATE TRIGGER replace_empty_username
AFTER UPDATE OF username ON user_temp
FOR EACH ROW
WHEN (NEW.username = '' AND OLD.id = NEW.id)
EXECUTE PROCEDURE replace_empty_username_with_null();
The expression NEW.id = OLD.id makes sense in the WHEN clause of the trigger ("ID did not change and is not null"). But it makes no sense in the body of the trigger function, where it burns down to TRUE. Also, to only affect the row which is being updated, just use a BEFORE trigger instead:
CREATE OR REPLACE FUNCTION replace_empty_username_with_null()
RETURNS TRIGGER LANGUAGE plpgsql AS
$func$
BEGIN
NEW.username = null; -- !
RETURN NEW;
END
$func$
CREATE TRIGGER replace_empty_username
BEFORE UPDATE OF username ON user_temp -- !
FOR EACH ROW
WHEN (NEW.username = '' AND OLD.id = NEW.id)
EXECUTE PROCEDURE replace_empty_username_with_null();
Related:
PostgreSQL Update trigger
I need help with my trigger. For example i have Query like this
INSERT INTO test(id_users,id_type,id_color) VALUES(1,3,4);
in my data base i have table with name: test
ghost, id, id_users, id_type, id_color
and i need before insert or update to check
Create trigger
Begin
select id from test where ghost = false and id_users = 26 and id_type = 3
if NO execute INSERT
if YEST exit with no action
END
How can i creat this trigger ?
There are two ways, depending on how you want to manage the problem.
If you wish to silence it, use a before trigger and return null:
create function ignore_invalid_row() returns trigger as $$
begin
if not exists(
select 1
from test
where not ghost
and id_users = new.id_users
and id_type = new.id_type
)
then
return null;
end if;
return new;
end;
$$ language plpgsql;
create trigger ignore_invalid_row_tg before insert on test
for each row execute procedure ignore_invalid_row();
If you wish to raise it, use a constraint trigger and raise an exception:
create function reject_invalid_row() returns trigger as $$
begin
if not exists(
select 1
from test
where not ghost
and id_users = new.id_users
and id_type = new.id_type
)
then
raise exception 'message';
end if;
return null;
end;
$$ language plpgsql;
create constraint trigger reject_invalid_row_tg after insert on test
for each row execute procedure reject_invalid_row();
http://www.postgresql.org/docs/current/static/sql-createtrigger.html
First, you need to create a trigger function and then the trigger, based on it:
CREATE OR REPLACE FUNCTION my_trigger_function() RETURNS TRIGGER AS $BODY$ BEGIN
IF EXISTS (SELECT id FROM test WHERE ghost = false AND id_users = 26 AND id_type = 3) THEN
return NEW;
ELSE
return NULL;
END IF; END; $BODY$ LANGUAGE 'plpgsql';
Then, you create trigger based on this function:
CREATE TRIGGER t_my_trigger BEFORE INSERT ON test FOR EACH ROW EXECUTE PROCEDURE my_trigger_function();
For more on triggers, see postgres docs.