I have a table:
CREATE TABLE annotations
(
gid serial NOT NULL,
annotation character varying(250),
the_geom geometry,
"rotationAngle" character varying(3) DEFAULT 0,
CONSTRAINT annotations_pkey PRIMARY KEY (gid),
CONSTRAINT enforce_dims_the_geom CHECK (st_ndims(the_geom) = 2),
CONSTRAINT enforce_srid_the_geom CHECK (st_srid(the_geom) = 4326)
)
And trigger:
CREATE TRIGGER set_angle
AFTER INSERT OR UPDATE
ON annotations
FOR EACH ROW
EXECUTE PROCEDURE setangle();
And function:
CREATE OR REPLACE FUNCTION setAngle() RETURNS TRIGGER AS $$
BEGIN
IF TG_OP = 'INSERT' THEN
UPDATE annotations SET "rotationAngle" = degrees( ST_Azimuth( ST_StartPoint(NEW.the_geom), ST_EndPoint(NEW.the_geom) ) )-90 WHERE gid = NEW.gid;
RETURN NEW;
ELSIF TG_OP = 'UPDATE' THEN
UPDATE annotations SET "rotationAngle" = degrees( ST_Azimuth( ST_StartPoint(NEW.the_geom), ST_EndPoint(NEW.the_geom) ) )-90 WHERE gid = NEW.gid;
RETURN NEW;
END IF;
END;
$$ LANGUAGE plpgsql;
And when new row inserted in table or row edited i want to field rotationAngle setted with function result.
But when i inserting a new row in table function not work. I mean thath rotationAngle value not changed.
What can be wrong?
You are triggering an endless loop. Simplify the trigger function:
CREATE OR REPLACE FUNCTION set_angle()
RETURNS trigger
LANGUAGE plpgsql AS
$func$
BEGIN
NEW."rotationAngle" := degrees(
ST_Azimuth(
ST_StartPoint(NEW.the_geom)
, ST_EndPoint(NEW.the_geom)
)
) - 90;
RETURN NEW;
END
$func$;
Assign to NEW directly. No WHERE in this case.
You must double-quote illegal column names. Better not to use such names to begin with.
Recent related answer.
Code for insert & upgrade is the same. I folded into one code path.
Use a BEFORE trigger. This way you can edit columns of the triggering row directly before they are saved:
CREATE TRIGGER set_angle
BEFORE INSERT OR UPDATE ON annotations
FOR EACH ROW EXECUTE PROCEDURE set_angle();
However
If you are just trying to persist a functionally dependent value in the table (and there are no other considerations): Don't. Use a view or a generated column instead:
Store common query as column?
Then you don't need any of this.
There are multiple things wrong here.
1) When you insert a row 'A' the function setAngle() is called. But in the function you are calling another update within the function which will trigger the function again, and again, and so on...To fix this don't issue a update! Just update the NEW records value independently and return it.
Related
Is there any variant to create a trigger before insert and if the value is a value that exists already in table, just update it. I know about 'ON DUBLICATE KEY' or a 'ON CONFLICT' in PostgreSQL but I need a trigger just because it's a task in my university.
I tried to create it, but I get just an error about duplicate keys.
CREATE or replace FUNCTION trigger_function()
RETURNS TRIGGER
LANGUAGE PLPGSQL
AS $$
BEGIN
IF new.name in (select name from "Test")
then
update "Test" set intt = new.intt where name = new.name;
end if ;
return new;
END;
$$
CREATE TRIGGER trigger_name
BEFORE insert
ON "Test"
for each row
EXECUTE PROCEDURE trigger_function();
Is it possible to create such trigger?
Read the docs plpgsql trigger function:
Row-level triggers fired BEFORE can return null to signal the trigger manager to skip the rest of the operation for this row (i.e., subsequent triggers are not fired, and the INSERT/UPDATE/DELETE does not occur for this row).
So RETURN NULL after the UPDATE statement inside the if andRETURN NEW when the if is false. Then the INSERT will happen if the name is unique.
So. I tried made a trigger for updating quality medicament( i take quality from delivery.quality and put in medicaments.quality)
create or replace function addedmed()
returns trigger
language plpgsql
as
$$
begin
update medicaments set medicaments.quality = delivery.quality + medicaments.quality
where medicaments.id_med = delivery.id_med_del;
end;
$$;
and then - i try insert data to delivery
insert into delivery(id_del,id_provider,date_of_get,id_worker_del,id_med_del,quality)
values (default, 3 , current_timestamp ,1 ,6 ,10);
and then i have a exception -
ЗАПРОС: update medicaments set medicaments.quality = delivery.quality + medicaments.quality
where medicaments.id_med = delivery.id_med_del
КОНТЕКСТ: PL/pgSQL function addedmed() line 3 at SQL statement
so, pls help me, because i dont know how resolve it
This is not valid trigger function code. If you want to refer to the row being inserted in delivery, then use pseudo-table new, not delivery.
create or replace function addedmed()
returns trigger
language plpgsql
as $$
begin
update medicaments set quality = quality + new.quality where id_med = new.id_med_del;
return new;
end;
$$;
Note that the trigger returns the new record. You can then actually create the trigger as follows:
create trigger trg_addedmed
before insert on delivery
for each row
execute addedmed()
;
I defined a before insert trigger, you can change that to after insert if you prefer (in that case you can return null instead of new).
I have the requirement to move data from one table to another table when the value of one of the columns is updated. And I just want to move the updated row to the new table.
Below is my trigger that I have written. The issue with my code is, that it is moving all the data and not just the row which was updated. Can anyone give a suggestion?
create or replace function moveToAC1ControlHist()
returns trigger as $$
begin if NEW.file_status='CO'
then
insert into ac1_control_hist (file_status,identitifier)
(
select file_status,identitifier
from
ac1_control where new.FILE_STATUS = 'CO'
);
end if;
return new;
end;
$$ language plpgsql;
create TRIGGER AC1_CONTROL_TRIGGER AFTER update of file_status ON AC1_CONTROL
FOR EACH ROW when (new.file_status ='CO')EXECUTE PROCEDURE moveToAC1ControlHist();
I think the logic you want is:
create or replace function moveToAC1ControlHist()
returns trigger as
$$
begin
insert into ac1_control_hist (file_status,identitifier)
values (new.file_status, new.identitifier);
return null;
end;
$$ language plpgsql;
create trigger ac1_control_trigger
after update of file_status on ac1_control
for each row
when (new.file_status ='co')
execute function movetoac1controlhist()
;
Rationale:
you just want to copy (part of) the row being updated, so there is no need to select; you can access the values of the current row with new in a row-level trigger
the trigger definition filters on new file_status that is equal to 'CO', so there is no need for a if construct in the function
this is an after trigger, so you can just return null - the result is discarded anyway
I have a table names Locations. It has columns [ID, GUID_ID, NAME, GEOMETRY]. I want to update GUID_ID column after a row inserted. So I will create a trigger to do this.
CREATE TRIGGER update_id
AFTER INSERT ON Locations
?? (How can Update GUID_ID column as uuid_generate_v4())
I set a default value for this column. But third party applications like QGIS inserts thousands of geometry records at same time. So the default value does not fill all columns. They are null. So I need trigger for solution.
I think it dosnt matter how much records QGIS enters, if you have defined a default value for field. May be QGIS is entering empty space instead. You can also add "NOT NULL" constraint in the field definition.
However trigger can be used like this. I am setting the GUID_ID value BEFORE INSERTING though.
CREATE TRIGGER update_id
BEFORE INSERT ON Locations
FOR EACH ROW EXECUTE PROCEDURE fn_trgr();
CREATE OR REPLACE FUNCTION fn_trgr() RETURNS TRIGGER AS $$
BEGIN
IF pg_trigger_depth() <> 1 THEN
RETURN NEW;
END IF;
NEW.GUID_ID = uuid_generate_v4(); -- or whatever value you wants to set
RETURN NEW;
END;
$$ LANGUAGE plpgsql;
How can I tell Postgres that a column with an empty string should use the DEFAULT value?
Using CHECK doesn't seem to work here.
A check constraint will only prevent putting such a value into the column. It will not magically replace the supplied value with the default value.
In order to silently replace an empty string (or null) with the value 'active' you will need a trigger:
create or replace function check_default()
returns trigger
as
$body$
begin
if (new.status is null or new.status = '') then
new.status = 'active';
end if;
return new;
end;
$body$
language plpgsql;
The above trigger would catch stuff like this:
insert into foo (id, active)
values (42,'');
update foo
set active = ''
where id = 42;
You could even extend that logic to also replace whitespace only values (' ') with the desired value.
Although it is possible to retrieve the default value dynamically in the trigger (to avoid having the same constant in two places) I would not do that for performance reasons.