here I want to trigger the update query if any one of the columns are updated. But I am getting error table table is mutating, trigger/function may not see it.
create or replace
TRIGGER TRIGGER1
AFTER UPDATE OF HOST_ID,ENABLED_FLAG,ACTIVE_FLAG,AGENT_COUNTER,USER_WAIT_FLAG ON MONITOR_AGENT_STATUS
FOR EACH ROW
BEGIN
update monitor_agent_status set active_flag='Y', enabled_flag='Y', agent_counter=0, user_flag='N';
END;
You should set the values like this in a BEFORE row trigger:
create or replace
TRIGGER TRIGGER1
BEFORE UPDATE OF HOST_ID,ENABLED_FLAG,ACTIVE_FLAG,AGENT_COUNTER,USER_WAIT_FLAG ON MONITOR_AGENT_STATUS
FOR EACH ROW
BEGIN
:NEW.active_flag:='Y';
:NEW.enabled_flag:='Y';
:NEW.agent_counter:=0;
:NEW.user_flag:='N';
END;
Your second trigger (from comments below):
CREATE OR REPLACE TRIGGER TRIGGER11
BEFORE UPDATE OF HOST_ID ON HOST_CURR_TIME
FOR EACH ROW
DECLARE
NewHost_Time varchar(10);
BEGIN
select HOST_ID
into NewHost_Time
from HOST_CURR_TIME
where HOST_ID='ATLMB100';
:new.HOST_ID:= case :new.HOST_ID
when 'CCNAFE02' then NewHost_Time
when 'OFCBSERV' then NewHost_Time
else :new.HOST_ID
end;
END;
Related
A trigger works on the first part of a function but not the second.
I'm trying to set up a trigger that does two things:
Update a field - geom - whenever the fields lat or lon are updated, using those two fields.
Update a field - country - from the geom field by referencing another table.
I've tried different syntaxes of using NEW, OLD, BEFORE and AFTER conditions, but whatever I do, I can only get the first part to work.
Here's the code:
CREATE OR REPLACE FUNCTION update_geometries()
RETURNS TRIGGER
LANGUAGE plpgsql
AS $$
BEGIN
update schema.table a set geom = st_setsrid(st_point(a.lon, a.lat), 4326);
update schema.table a set country = b.name
from reference.admin_layers_0 b where st_intersects(a.geom,b.geom)
and a.pk = new.pk;
RETURN NEW;
END;
$$;
CREATE TRIGGER
geom_update
AFTER INSERT OR UPDATE of lat,lon on
schema.table
FOR EACH STATEMENT EXECUTE PROCEDURE update_geometries();
There is no new on a statement level trigger. (well, there is, but it is always Null)
You can either keep the statement level and update the entire a table, i.e. remove the and a.pk = new.pk, or, if only part of the rows are updated, change the trigger for a row-level trigger and only update the affected rows
CREATE OR REPLACE FUNCTION update_geometries()
RETURNS TRIGGER
LANGUAGE plpgsql
AS $$
BEGIN
NEW.geom = st_setsrid(st_point(NEW.lon, NEW.lat), 4326);
SELECT b.name
INTO NEW.country
FROM reference.admin_layers_0 b
WHERE st_intersects(NEW.geom,b.geom);
RETURN NEW;
END;
$$;
CREATE TRIGGER
geom_update
BEFORE INSERT OR UPDATE of lat,lon on
schema.table
FOR EACH ROW EXECUTE PROCEDURE update_geometries();
I am looking for an elegant solution to this situation:
I have created a trigger function that updates the table supply with the sum of some detail rows, whenever a row is inserted or updated on warehouse_supplies.
PostgreSQL insert or update syntax allowed me to share the same function sync_supply_stock() for the insert and update conditions.
However, when I try to wire the after delete condition to the function it cannot be reused (although it is logically valid), for the returning object must be old instead of new.
-- The function I want to use for the 3 conditions (insert, update, delete)
create or replace function sync_supply_stock ()
returns trigger
as $$
begin
-- update the supply whose stock just changed in warehouse_supply with
-- the sum its stocks on all the warehouses.
update supply
set stock = (select sum(stock) from warehouse_supplies where supply_id = new.supply_id)
where supply_id = new.supply_id;
return new;
end;
$$ language plpgsql;
-- The (probably) unnecessary copy of the previous function, this time returning old.
create or replace function sync_supply_stock2 ()
returns trigger
as $$
begin
-- update the supply whose stock just changed in warehouse_supply with
-- the sum its stocks on all the warehouses.
update supply
set stock = (select sum(stock) from warehouse_supplies where supply_id = old.supply_id)
where supply_id = old.supply_id;
return old;
end;
$$ language plpgsql;
-- The after insert/update trigger
create trigger on_warehouse_supplies__after_upsert after insert or update
on warehouse_supplies for each row
execute procedure sync_supply_stock ();
-- The after delete trigger
create trigger on_warehouse_supplies__after_delete after delete
on warehouse_supplies for each row
execute procedure sync_supply_stock2 ();
Am I missing something or is there any fixing to duplicating sync_supply_stock2() as sync_supply_stock2()?
EDIT
For the benefit of future readers, following #bergi answer and discusion, this is a possible factorized solution
create or replace function sync_supply_stock ()
returns trigger
as $$
declare
_supply_id int;
begin
-- read the supply_id column from `new` on insert/update conditions and from `old` on delete conditions
_supply_id = coalesce(new.supply_id, old.supply_id);
-- update the supply whose stock just changed in of_warehouse_supply with
-- the sum its stocks on all the warehouses.
update of_supply
set stock = (select sum(stock) from of_warehouse_supplies where supply_id = _supply_id)
where supply_id = _supply_id;
-- returns `new` on insert/update conditions and `old` on delete conditions
return coalesce(new, old);
end;
$$ language plpgsql;
create trigger on_warehouse_supplies__after_upsert after insert or update
on of_warehouse_supplies for each row
execute procedure sync_supply_stock ();
create trigger on_warehouse_supplies__after_delete after delete
on of_warehouse_supplies for each row
execute procedure sync_supply_stock ();
for the returning object must be old instead of new.
No. The return value is only relevant for BEFORE ROW or INSTEAD OF triggers. From the docs: "The return value of a row-level trigger fired AFTER or a statement-level trigger fired BEFORE or AFTER is always ignored; it might as well be null".
So you can just make your sync_supply_stock trigger function RETURN NULL and it can be used on all operations.
I try to automatize some calculations on tables in my database. I try to perform some UPDATE on rows that are newly inserted in a table, but I newer used NEW or OLD statements before. I tried writing the code that updates happen on new values by assigning NEW.[tablename], but it wont work. Isn't there any statement in the beginning of the trigger function to specify running the function only on new values, I cannot find useful information about this.
CREATE OR REPLACE FUNCTION cost_estimation()
RETURNS TRIGGER AS
$func$
DECLARE
a INTEGER := 3;
BEGIN
UPDATE NEW.cost_table
SET column4 = a;
UPDATE NEW.cost_table
SET column 5 = column4 - column2;
[...]
RETURN NEW;
END
$func$ language plpgsql
UPDATE:
Thank you for the answers so far.
My original code is written based on the update structure, and needs to be rewritten when omitting UPDATE. I should give a better example of my situation. Easy spoken: I have a table (T1) which will be filled with data from another table (T2).
After data is inserted in T1 from T2 I want to run calculations on the new values inside of T1.(The code includes PostGIS functionalities):
CREATE OR REPLACE FUNCTION cost_estimation()
RETURNS TRIGGER AS
$func$
BEGIN
NEW.column6 = column2 FROM external_table WHERE
St_Intersects(NEW.geom, external_table.geom) LIMIT1;
NEW.column8 = CASE
WHEN st_intersects(NEW.geom, external_table2.geom) then 'intersects'
WHEN (NEW.column9 = 'K' and NEW.column10 <= 6) then 'somethingelse'
ELSE 'nothing'
END
FROM external_table2;
[...]
RETURN NEW;
END
$func$ language plpgsql
CREATE TRIGGER table_calculation_on_new
BEFORE INSERT OR UPDATE ON cost_estimation
FOR EACH ROW EXECUTE PROCEDURE road_coast_estimation();
After inserting values in my table no calculations will be performed.
UPDATE2: I checked my tables again and detected that another trigger was blocking the table operation. The code in the lower half is working fine now, thanks to #a_horse_with_no_name.
NEW and OLD aren't "statements", those are records that represent the modified rows from the DML statement that fired the trigger.
Assuming the trigger is defined on cost_table you can simply change the fields in the NEW record. No need to UPDATE anything:
CREATE OR REPLACE FUNCTION cost_estimation()
RETURNS TRIGGER AS
$func$
DECLARE
a INTEGER := 3;
BEGIN
new.column4 := a;
new.column5 := new.column4 - new.column2;
return new;
END;
$func$ language plpgsql
For this to work the trigger needs to be defined as a BEFORE trigger:
create trigger cost_table_trigger
BEFORE insert or update on cost_table
for each row execute procedure cost_estimation();
I have this table for which one of the columns is to be filled with values from other columns of the same table (these other columns represent a taxonomic hierarchy whose lowest level I wish to store in this other column).
To achieve this I implemented the following trigger:
CREATE OR REPLACE FUNCTION get_taxon()
RETURNS TRIGGER LANGUAGE plpgsql AS
$BODY$
BEGIN
UPDATE taxon SET taxon = coalesce(subespecie, especie, genero, subfamilia, familia, infraordem, subordem, ordem, superordem, subclasse, classe, subphylum, phylum, reino )
WHERE taxon IS NULL;
RETURN NEW;
END
$BODY$
VOLATILE;
CREATE TRIGGER update_taxon
AFTER INSERT OR UPDATE ON taxon
FOR EACH STATEMENT
WHEN (pg_trigger_depth() = 0) -- Prevent recursive trigger calls
EXECUTE PROCEDURE get_taxon();
When I insert a new record the trigger works as expected, but if I update an existing record, nothing happens - the trigger just ignores UPDATE operations and I don't know why.
Can anyone shed some light on this please?
After your statement trigger first fired all records in the table should have their taxon field updated with the best available information. When you update a record you may want to update the taxon value, but you are better off with a BEFORE INSERT OR UPDATE FOR EACH ROW trigger. The only new data is contained in the row for which the trigger fires, of course. So try this:
CREATE OR REPLACE FUNCTION get_taxon()
RETURNS TRIGGER LANGUAGE plpgsql AS
$BODY$
BEGIN
NEW.taxon := coalesce(NEW.subespecie, NEW.especie, NEW.genero, NEW.subfamilia,
NEW.familia, NEW.infraordem, NEW.subordem, NEW.ordem, NEW.superordem,
NEW.subclasse, NEW.classe, NEW.subphylum, NEW.phylum, NEW.reino);
RETURN NEW;
END;
$BODY$ VOLATILE;
CREATE TRIGGER update_taxon
BEFORE INSERT OR UPDATE ON taxon
FOR EACH ROW EXECUTE PROCEDURE get_taxon();
I need help in Postgres triggers.
I have table with 2 columns:
sold boolean;
id_shop int;
It stores if item is sold, or at which shop its located at.
I need a trigger, if I change the "sold" to true, then it also changes the id_shop to NULL (It can't be in shop if sold...)
I tried different ways, but it doesn't work or gives an error on update cmd...
create or replace function pardota_masina_veikals() RETURNS trigger AS $pardota_masina$
begin
IF NEW.sold=true THEN
update masinas
SET id_shop=null WHERE id=NEW.id;
END IF;
RETURN NEW;
END;
$pardota_masina$ LANGUAGE plpgsql;
CREATE TRIGGER pardota_masina_nevar_but_veikala
AFTER INSERT OR UPDATE ON masinas FOR EACH ROW EXECUTE PROCEDURE pardota_masina_veikals();
First of all you need a before trigger if you want to change a value of the row being updated (or inserted)
Secondly you don't need to "update" the table, just assign the new value to the NEW row:
create or replace function pardota_masina_veikals()
RETURNS trigger
AS
$pardota_masina$
begin
IF NEW.sold=true THEN
NEW.id_shop = NULL;
END IF;
RETURN NEW;
END;
$pardota_masina$
LANGUAGE plpgsql;
CREATE TRIGGER pardota_masina_nevar_but_veikala
BEFORE INSERT OR UPDATE ON masinas
FOR EACH ROW EXECUTE PROCEDURE pardota_masina_veikals();