I created a Trigger on Update which should insert in my table preishist.
//preishist
CREATE TABLE preishist (
updatenr varchar(4),
preis numeric(8,2),
pnr varchar(4),
gueltigab date,
PRIMARY KEY(updatenr));
//produkt
CREATE TABLE produkt(
pnr varchar(4),
name varchar(4),
preis numeric(8,2),
gultigab date,
PRIMARY KEY(pnr));
//Trigger
CREATE TRIGGER trigger AFTER UPDATE ON produkt FOR EACH STATEMENT EXECUTE
PROCEDURE triggerfunc();
//Triggerfunc
CREATE FUNCTION triggerfunc RETURNS TRIGGER AS '
begin
IF TG_OP = 'UPDATE' THEN
IF OLD.preis <> NEW.preis AND OLD.gueltigab < NEW.gueltigab THEN
INSERT INTO preishist (preis,pnr,gultigab) VALUES (NEW.preis, NEW.pnr,NEW.gueltigab);
end IF;
end IF;
end;
When I try to update produkt I get the error message
Record old is not assigned yet.
I'm happy for all help.
OLD and NEW are only available in row level trigger. You defined your trigger as a statement level trigger.
To be able to use OLD and NEW use:
CREATE TRIGGER trigger
AFTER UPDATE ON produkt
FOR EACH ROW --<< here
EXECUTE PROCEDURE triggerfunc();
Related
here is my script:
CREATE SCHEMA IF NOT EXISTS {accountId};
CREATE TABLE IF NOT EXISTS {accountId}.{tableCommandsName}
(
id int GENERATED ALWAYS AS IDENTITY,
ts timestamp WITHOUT TIME ZONE NOT NULL,
command varchar NOT NULL,
ts_executed timestamp WITHOUT TIME ZONE,
output varchar
);
CREATE INDEX IF NOT EXISTS idx_commands ON {accountId}.{tableCommandsName} (ts_executed) WHERE ts_executed IS NULL;
CREATE OR REPLACE VIEW {accountId}.pending_commands AS
SELECT id, ts, command from {accountId}.{tableCommandsName} WHERE ts_executed IS NULL ORDER BY ts ASC;
CREATE OR REPLACE FUNCTION {accountId}.on_commands_change ()
RETURNS trigger
LANGUAGE 'plpgsql'
AS $BODY$
DECLARE
notification JSON;
BEGIN
notification = json_build_object(
'table',TG_TABLE_NAME,
'data', row_to_json(NEW));
PERFORM pg_notify('datachange', notification::TEXT);
RETURN NEW;
END
$BODY$;
CREATE OR REPLACE TRIGGER {triggerName}
AFTER INSERT ON {accountId}.{tableCommandsName}
FOR EACH ROW EXECUTE PROCEDURE {accountId}.on_commands_change();
my focus is the line:
CREATE OR REPLACE TRIGGER {triggerName}
where
CREATE OR REPLACE TRIGGER {accountId}.{triggerName}
will not work, but
CREATE OR REPLACE TRIGGER "{accountId}.{triggerName}"
will work, and I don't understand why.
everything else has the schema name in front, but the trigger doesn't want it.
and if I don't put it, it's still created in the right schema. Is it because it's during the same execution as the create schema instruction?
Quote from the manual
The name cannot be schema-qualified — the trigger inherits the schema of its table
I have this table on PostgreSQL and I'd like to make a trigger that every time I edit one row of the table publications the last_edit_date is updated to now():
CREATE FUNCTION trigger_update_question_timestamp()
RETURNS "trigger" AS $func$
BEGIN
UPDATE publications SET last_edit_date = now() WHERE publicationid = NEW.publicationid;
RETURN NULL;
END;
$func$ LANGUAGE plpgsql;
CREATE TRIGGER answer_update_question_timestamp AFTER INSERT OR UPDATE ON publications
FOR EACH ROW EXECUTE PROCEDURE trigger_update_question_timestamp();
CREATE TABLE publications
(
publicationid SERIAL PRIMARY KEY,
body VARCHAR(1000) NOT NULL ,
creation_date TIMESTAMP DEFAULT now() NOT NULL,
userid INTEGER NOT NULL,
last_edit_date TIMESTAMP,
CONSTRAINT body_length CHECK (CHAR_LENGTH(body) >= 10 AND CHAR_LENGTH(body) <= 1000),
CONSTRAINT "FK_publications_users"
FOREIGN KEY ("userid") REFERENCES users ("userid") ON DELETE SET NULL ON UPDATE CASCADE
);
I'm using PhpStorm and when I manually edit a line I get the following error:
[54001] ERROR: stack depth limit exceeded Hint: Increase the configuration parameter "max_stack_depth" (currently 2048kB), after ensuring the platform's stack depth limit is adequate. Where: SQL statement "SELECT 1 FROM ONLY "public"."users" x WHERE "userid" OPERATOR(pg_catalog.=) $1 FOR KEY SHARE OF x" SQL statement "UPDATE publications SET last_edit_date = now() WHERE publicationid = NEW.publicationid" PL/pgSQL function trigger_update_question_timestamp()
What does this exactly means? Does it have to do with my trigger or any other definition?
Your trigger is recursive, that is, the trigger function executes an UPDATE that calls the trigger function again.
The solution here is to use a BEFORE INSERT OR UPDATE trigger, that modifies NEW as follows:
BEGIN
NEW.last_edit_date := current_timestamp;
RETURN NEW;
END;
Here is my sample table.
CREATE TABLE employee_test(
idTst SERIAL PRIMARY KEY,
monthDownload VARCHAR(6),
changeDate DATE);
I am trying to create a function and trigger that would update changeDate attribute with a current date when monthDownload attribute is updated.
The function I have it works with one problem. It updates all records instead of the one that was updated.
CREATE OR REPLACE FUNCTION downloadMonthChange()
RETURNS TRIGGER AS
$$
BEGIN
IF NEW.monthDownload <> OLD.monthDownload THEN
UPDATE employee_test
SET changeDate = current_date
where OLD.idTst = NEW.idTst;
END IF;
RETURN NEW;
END;
$$
Language plpgsql;
Trigger
Create TRIGGER dataTest
AFTER UPDATE
ON employee_test
FOR EACH ROW
EXECUTE PROCEDURE downloadMonthChange();
When I execute the following Update statement:
UPDATE employee_test SET monthDownload = 'oct12'
WHERE idTst = 1;
All changeDate rows get update with a current date.
Is there a way to have only a row with changed record to have a current date updated.
If you use a before trigger you can write directly to NEW
CREATE OR REPLACE FUNCTION downloadMonthChange()
RETURNS TRIGGER AS
$$
BEGIN
IF NEW.monthDownload <> OLD.monthDownload THEN
NEW.changeDate = current_date;
END IF;
RETURN NEW;
END;
$$
Language plpgsql;
the other option when you must use an after trigger is to include the primary key in the where clause. It appears that you were trying to do this, but you had a spurious OLD in the query. beause of that the where clause was only looking at the record responsible for the trigger call, and not limiting which records were to be updated.
IF NEW.monthDownload <> OLD.monthDownload THEN
UPDATE employee_test
SET changeDate = current_date
where idTst = NEW.idTst;
I am trying to learn Postgres triggers, using some simple examples. I have created a simple table:
create table emp (empname text, salary integer, last_user text);
My goal is to replace the old salary with a new salary computed as the salary inserted (new) + the old salary. I could not get them to sum even when I did not put a condition (i.e. empname is the same)
Here is my code:
-- this table returns a new row instead of summing
CREATE OR REPLACE FUNCTION emp_stamp() RETURNS trigger
AS $emp_stamp$
BEGIN
new.salary = new.salary + old.salary ;
RETURN NEW;
END;
$emp_stamp$ LANGUAGE plpgsql;
CREATE TRIGGER emp_stamp
BEFORE UPDATE on emp
FOR EACH ROW
EXECUTE PROCEDURE emp_stamp();
When I insert into the table, I get a new row added and no existing rows follow the formula:
INSERT INTO EMP VALUES('BR',39970,'BR')
I have also unsuccessfully tried the UPDATE command.
Your CREATE TRIGGER script says BEFORE UPDATE. So this trigger is not fired at all for INSERT commands.
Moreover, the same trigger function would raise an error for INSERT commands anyway because, obviously, there is no "old" version for newly inserted rows.
It should work just fine as is for UPDATE, though. I just cleaned it up a bit:
CREATE OR REPLACE FUNCTION emp_stamp()
RETURNS trigger AS
$func$
BEGIN
NEW.salary := NEW.salary + OLD.salary;
RETURN NEW;
END
$func$ LANGUAGE plpgsql;
CREATE TRIGGER emp_stamp
BEFORE UPDATE ON emp
FOR EACH ROW EXECUTE PROCEDURE emp_stamp();
Just a proof of concept, I fail to see the point of adding up old an new value.
For starters, your table needs a proper PRIMARY KEY, a serial column for instance (empname is hardly unique):
CREATE TABLE emp (
emp_id serial PRIMARY KEY
, empname text
, salary integer
, last_user text);
Then the UPDATE could work reliably:
UPDATE EMP
SET salary = 39970
WHERE emp_id = 123;
I still don't see how the mentioned trigger would make sense. You could increase an existing salary like this, no trigger involved:
UPDATE EMP
SET salary = salary + 39970
WHERE emp_id = 123;
Is it possible to dynamically change column values in NEW with a Trigger Function?
Triggers:
CREATE TRIGGER lowercase_username_on_insert_trigger BEFORE INSERT OR UPDATE ON users
FOR EACH ROW EXECUTE PROCEDURE lowercase_on_insert('username');
CREATE TRIGGER lowercase_email_on_insert_trigger BEFORE INSERT OR UPDATE ON users
FOR EACH ROW EXECUTE PROCEDURE lowercase_on_insert('email');
Trigger Function:
CREATE OR REPLACE FUNCTION lowercase_on_insert()
RETURNS trigger
AS $lowercase_on_insert$
BEGIN
-- e.g., NEW.username = LOWER(NEW.username)
-- -OR- NEW.email = LOWER(NEW.email)
EXECUTE FORMAT('NEW.%s = LOWER(NEW.%s);', TG_ARGV[0], TG_ARGV[0]);
RETURN NEW;
END
$lowercase_on_insert$ LANGUAGE plpgsql;
I get an ERROR: syntax error at or new "NEW" whenever I run an INSERT.
This is my table:
CREATE TABLE users (
id BIGSERIAL PRIMARY KEY,
username VARCHAR(55) NOT NULL UNIQUE,
email VARCHAR(120) NOT NULL UNIQUE
);
Change your Trigger function as below
CREATE OR REPLACE FUNCTION lowercase() RETURNS trigger AS $$
BEGIN
NEW.username = LOWER(NEW.username);
NEW.email = LOWER(NEW.email);
RETURN NEW;
END;
$$ LANGUAGE plpgsql;
and assign
CREATE TRIGGER tgrr BEFORE INSERT OR UPDATE ON users
FOR EACH ROW EXECUTE PROCEDURE lowercase();
OR
You can directly apply lower() function in Insert/Update like this
insert into users(username,email) values (lower('Jerry'),lower('JeRRY#mail.COM'));
update users set username=lower('JERRY'),email=lower('JERRY#MAIL.COM') where id =1