Triggers PostgreSQL - postgresql

I have an exercise on triggers in PostgreSQL.
I have 2 tables : "commande" and "ligne_commande".
In the table "ligne_commande" there are 4 columns :
codecommande - codeligne - quantité - codepdt
In the table "commande" there are 6 columns :
codecommande - datecommande - montantht - codeclient - codevendeur - coderemise
I need to create a trigger that for each modification / insertion / deletion in ligne_commande calculate the amount of an order (montantht in the table commande).
I already have the following function that calculate the amount of an order (made in a previous exercise) :
CREATE OR REPLACE FUNCTION verifmontantht(VARCHAR(10)) RETURNS boolean AS '
DECLARE
verifmontantht commande.montantht%TYPE;
BEGIN
SELECT INTO verifmontantht (SUM(produit.prixpdt * ligne_commande.quantite) * (100 - COALESCE(commande.coderemise,0))/100)::numeric(7,2) AS "Montant vérifié"
FROM commande JOIN ligne_commande ON commande.codecommande = ligne_commande.codecommande
JOIN produit ON ligne_commande.codepdt = produit.codepdt
WHERE commande.codecommande = $1
GROUP BY commande.codecommande, commande.datecommande, commande.montantht, commande.coderemise
ORDER BY commande.codecommande;
END;
'
LANGUAGE 'plpgsql';
I can't find a way to make a trigger that can use this function or should I create another function because this one doesn't have RETURN TRIGGER AS $..$
Do you have any advice that could help me ? Because I'm really stuck on that one..
Thank you very much for you help :)

Related

How to make a self referential window functions

I have a table like this:
amount type app owe
1 a 10 10
2 a 8 -2
3 a 20 12
4 i 30 10
5 a 40 10
owe is:
(type == 'a')?app - sum(owe) where amount < (amount for current row):max(app-sum(owe)where amount<(amount for current row),0)
So I'd need a window function on the column that the window function is on. There are these partition on rows between rows unlimited preceding and prior row, but it has to be on a different column, not the column I'm summing. Is there a way to reference the same column the window function is on
I tried an alias
case
when type = a
then app - sum(owe)over(ROWS BETWEEN UNBOUNDED PRECEDING AND 1 preceding) as owe
else
greatest(0,app - sum(owe)over(ROWS BETWEEN UNBOUNDED PRECEDING AND 1 preceding))
end as owe
But since owe doesn't exist when I made it, I get:
owe doesn't exist.
Is there some other way?
You cannot do that with window functions. Your only chance using SQL is a recursive CTE:
WITH RECURSIVE tab_owe AS (
SELECT amount, type, app,
CASE WHEN type = 'a'
THEN app
ELSE GREATEST(app, 0)
END AS owe
FROM tab
ORDER BY amount LIMIT 1
UNION ALL
SELECT t.amount, t.type, t.app,
CASE WHEN t.type = 'a'
THEN t.app - sum(tab_owe.owe)
ELSE GREATEST(t.app - sum(tab_owe.owe), 0)
END AS owe
FROM (SELECT amount, type, app
FROM tab
WHERE amount > (SELECT max(amount) FROM tab_owe)
ORDER BY amount
LIMIT 1) AS t
CROSS JOIN tab_owe
GROUP BY t.amount, t.type, t.app
)
SELECT amount, type, app, owe
FROM tab_owe;
(untested)
This would be much easier to write in procedural code, sou consider using a table function.
This is what I came up with. Of course, I'm not a real programmer, so I'm sure there's a smarter way:
insert into mort (amount, "type", app)
values
(1,'a',10),
(2,'a',8),
(3,'a',20),
(4,'i',30),
(5,'a',40)
CREATE OR REPLACE FUNCTION mort_v ()
RETURNS TABLE (
zamount int,
ztype text,
zapp int,
zowe double precision
) AS $$
DECLARE
var_r record;
charlie double precision;
sam double precision;
BEGIN
charlie = 0;
FOR var_r IN(SELECT
amount,
"type",
app
FROM mort order by 1)
LOOP
zamount = var_r.amount;
ztype = var_r.type;
zapp = var_r.app;
sam = var_r.app - charlie;
if ztype = 'a' then
zowe = sam;
else
zowe = greatest(sam, 0);
end if;
charlie = charlie + zowe;
RETURN NEXT;
END LOOP;
END; $$
LANGUAGE 'plpgsql';
select * from mort_v()
So with my limited skills you'll notice I had to add a 'z' in front of the columns that are already in the table so I can spit it out again. If your table has 30 columns you'd normally have to do this 30 times. But, I asked a real engineer and he mentioned that if you just spit out the primary key with the calculated column, you can just join it back to the original table. That's smarter than what I have. If there's an even better solution, that would be great. This does serve as a nice reference to how to do something like a cursor in postgre and how to make variables without a '#' in front like in mssqlserver.

How to use st_Line_Locate_Point() with a MULTILINESTRING convertion in PostGIS?

I am trying to get the index position of a POINT in a MULTILINESTRING.
Here is the whole query I'm stuck with :
SELECT req.id, (dp).geom, netgeo_point_tech.id, ST_Line_Locate_Point(st_lineMerge(geom_cable), (dp).geom)
FROM (SELECT id, ST_DumpPoints(geom) as dp, geom as geom_cable FROM netgeo_cable_test ) as req
JOIN netgeo_point_tech ON ST_dwithin(netgeo_point_tech.geom, (dp).geom, 1)
ORDER BY req.id, (dp).path [ 1] ASC
The error I get is : line_locate_point : 1st arg isnt a line.
The error is due to the return of st_lineMerge() function that is returning LINESTRING but also MULTILINESTRING.
I don't get this. st_lineMerge() is supposed to return only LINESTRING.ST_LineMerge()
When I jsut try a simple query like this :
select st_astext(st_linemerge(geom)) from netgeo_cable_test
The output is :
)
I want to learn from this, so, if possible, explain to me what I'm doing wrong here, or if my approach is lacking insight.
Thanks to #JGH for the suggestion to use ST_Dump I came up with this function:
create or replace function MultiLineLocatePoint(line geometry, point geometry) returns numeric as $$
select (base + extra) / ST_Length(line)
from (
select
sum(ST_Length(l.geom)) over (order by l.path) - ST_Length(l.geom) base,
ST_LineLocatePoint(l.geom, point) * ST_Length(l.geom) extra,
ST_Distance(l.geom, point) dist
from ST_Dump(line) l
) points
order by dist
limit 1;
$$ language SQL;

PostgreSQL function giving all rows but not in key value pair format?

I have table called users in PostgreSQL.I want to get all users in table from my Laravel application.
I can get from table directly as:
$testData = DB::table('users')->get();
output is:
[{"id":1,"name":"Chris Sevilleja","username":"sevilayha","email":"chris#scotch.io","password":"$2y$08$i\/ATa68ierqRL47ZxHX4EesJGEcdtKPckZs8GDGpYS.IR4aaQn.\/q","created_at":"2016-09-07 09:32:41","updated_at":"2016-09-07 09:32:41"},{"id":2,"name":"Bemagoni chandrashekar","username":"chandrashekar","email":"chandrashekar#zessta.com","password":"$2y$08$QG9JsAerYp3UYpXNNyImhuz\/6hiWv8XpURpJX1uJ.hAm8l1RG2JrC","created_at":"2016-09-07 09:32:41","updated_at":"2016-09-07 09:32:41"},{"id":3,"name":"dwefr","username":"ewre","email":"ewrt#egyfrhgt.com","password":"$2y$08$s2XBZvoAvpEqjjhbx8QPw.eSe5TIuJC25XbaFkTskzAKAGi99QWga","created_at":"2016-09-07 09:34:27","updated_at":"2016-09-07 09:34:27"},{"id":4,"name":"r3t54y6u677i","username":"retrytyu","email":"etyru#dddj.com","password":"$2y$08$Xb0Xm4KwdSwcBSHX0F6ETOWU60X.NO5D7\/uwVv\/xUAXTUS8LSPCLu","created_at":"2016-09-07 09:46:26","updated_at":"2016-09-07 09:46:26"},{"id":5,"name":"r3t45y6u","username":"ertrh","email":"435t4y65#sss.com","password":"$2y$08$36DLu49nZ2YOWtU.c625meiyi3\/fmsHxiTuxIU9z9UcyrbIpFSKKW","created_at":"2016-09-07 10:02:05","updated_at":"2016-09-07 10:02:05"},{"id":6,"name":"ewrtryuyj","username":"ryt","email":"wrewtey#sssks.com","password":"$2y$08$GULHtX3GGXPGgm8gA9yDbeawZlQ5QwD2TX7nrCvEU4j7jrSgPWAQO","created_at":"2016-09-07 10:04:17","updated_at":"2016-09-07 10:04:17"},{"id":7,"name":"chandu","username":"chandu","email":"ch1235hdhd#dhdjd.com","password":"$2y$08$gpAhcl\/Sg.lGvb.zk.I\/m.PfcttGI6OPFMsMxQVm15dYOtQDvIWSG","created_at":"2016-09-07 10:06:18","updated_at":"2016-09-07 10:06:18"},{"id":8,"name":"dewfergt","username":"erwrgf","email":"fgf#dgrf.com","password":"$2y$08$ikYAXV1prZsEj2MPxXM4S.Tqn160Jv25cFOQLghK8ptFiSBaIFGZO","created_at":"2016-09-07 10:07:20","updated_at":"2016-09-07 10:07:20"},{"id":9,"name":"rteryt","username":"wrwter","email":"wretr#gjjd.com","password":"$2y$08$pkOUBl1NlNdBShNWiklya.0zlPzPrEH2edCfvdCiHLnj80GY1sdtm","created_at":"2016-09-08 07:11:46","updated_at":"2016-09-08 07:11:46"},{"id":10,"name":"Raghu","username":"raghu","email":"raghu#gdgdjd.com","password":"$2y$08$m9wke.vvTTZytYw91I4\/q.qxKoCobLOW7dbCvs66xFyJyy2R9phni","created_at":"2016-09-10 10:06:40","updated_at":"2016-09-10 10:06:40"},{"id":11,"name":"wewert","username":"ewretr","email":"ewrtey#vsss.com","password":"$2y$08$IXD0eXYTPPGE1MfALonEFey0lr\/KBMZ0.3AIO3sWVgu7IZdWhXwTG","created_at":"2016-09-12 07:48:58","updated_at":"2016-09-12 07:48:58"}]
Through PostgreSQL function calling:
my PostgreSQL function:
-- Function: public."RegiterUsers2"()
-- DROP FUNCTION public."RegiterUsers2"();
CREATE OR REPLACE FUNCTION public."RegiterUsers2"()
RETURNS SETOF users AS
'select * from users'
LANGUAGE sql VOLATILE
COST 100
ROWS 1000;
ALTER FUNCTION public."RegiterUsers2"()
OWNER TO postgres;
Laravel code:
$allUserData=DB::select('SELECT public."RegiterUsers2"()')
output:
[{"RegiterUsers2":"(1,\"Chris Sevilleja\",sevilayha,chris#scotch.io,$2y$08$i\/ATa68ierqRL47ZxHX4EesJGEcdtKPckZs8GDGpYS.IR4aaQn.\/q,\"2016-09-07 09:32:41\",\"2016-09-07 09:32:41\")"},{"RegiterUsers2":"(2,\"Bemagoni chandrashekar\",chandrashekar,chandrashekar#zessta.com,$2y$08$QG9JsAerYp3UYpXNNyImhuz\/6hiWv8XpURpJX1uJ.hAm8l1RG2JrC,\"2016-09-07 09:32:41\",\"2016-09-07 09:32:41\")"},{"RegiterUsers2":"(3,dwefr,ewre,ewrt#egyfrhgt.com,$2y$08$s2XBZvoAvpEqjjhbx8QPw.eSe5TIuJC25XbaFkTskzAKAGi99QWga,\"2016-09-07 09:34:27\",\"2016-09-07 09:34:27\")"},{"RegiterUsers2":"(4,r3t54y6u677i,retrytyu,etyru#dddj.com,$2y$08$Xb0Xm4KwdSwcBSHX0F6ETOWU60X.NO5D7\/uwVv\/xUAXTUS8LSPCLu,\"2016-09-07 09:46:26\",\"2016-09-07 09:46:26\")"},{"RegiterUsers2":"(5,r3t45y6u,ertrh,435t4y65#sss.com,$2y$08$36DLu49nZ2YOWtU.c625meiyi3\/fmsHxiTuxIU9z9UcyrbIpFSKKW,\"2016-09-07 10:02:05\",\"2016-09-07 10:02:05\")"},{"RegiterUsers2":"(6,ewrtryuyj,ryt,wrewtey#sssks.com,$2y$08$GULHtX3GGXPGgm8gA9yDbeawZlQ5QwD2TX7nrCvEU4j7jrSgPWAQO,\"2016-09-07 10:04:17\",\"2016-09-07 10:04:17\")"},{"RegiterUsers2":"(7,chandu,chandu,ch1235hdhd#dhdjd.com,$2y$08$gpAhcl\/Sg.lGvb.zk.I\/m.PfcttGI6OPFMsMxQVm15dYOtQDvIWSG,\"2016-09-07 10:06:18\",\"2016-09-07 10:06:18\")"},{"RegiterUsers2":"(8,dewfergt,erwrgf,fgf#dgrf.com,$2y$08$ikYAXV1prZsEj2MPxXM4S.Tqn160Jv25cFOQLghK8ptFiSBaIFGZO,\"2016-09-07 10:07:20\",\"2016-09-07 10:07:20\")"},{"RegiterUsers2":"(9,rteryt,wrwter,wretr#gjjd.com,$2y$08$pkOUBl1NlNdBShNWiklya.0zlPzPrEH2edCfvdCiHLnj80GY1sdtm,\"2016-09-08 07:11:46\",\"2016-09-08 07:11:46\")"},{"RegiterUsers2":"(10,Raghu,raghu,raghu#gdgdjd.com,$2y$08$m9wke.vvTTZytYw91I4\/q.qxKoCobLOW7dbCvs66xFyJyy2R9phni,\"2016-09-10 10:06:40\",\"2016-09-10 10:06:40\")"},{"RegiterUsers2":"(11,wewert,ewretr,ewrtey#vsss.com,$2y$08$IXD0eXYTPPGE1MfALonEFey0lr\/KBMZ0.3AIO3sWVgu7IZdWhXwTG,\"2016-09-12 07:48:58\",\"2016-09-12 07:48:58\")"}]
I need like this
{"id":1,
"name":"Chris Sevilleja",
"username":"sevilayha",
"email":"chris#scotch.io",
"password":"$2y$08$i\/ATa68ierqRL47ZxHX4EesJGEcdtKPckZs8GDGpYS.IR4aaQn",
"created_at":"2016-09-07 09:32:41",
"updated_at":"2016-09-07 09:32:41"},
so what is wrong with postgres function and how can I get like above one.
When you call a function returning many columns and you want each one, you must call in the form of:
SELECT col1, col2, ... FROM function(...)
Or:
SELECT * FROM function(...)
So in your case you simple want:
$allUserData=DB::select('SELECT * FROM public."RegiterUsers2"()')

Firebird dynamic Var New and Old

I need validate dynamic Fields from a Table. For example:
CREATE TRIGGER BU_TPROYECTOS FOR TPROYECTOS
BEFORE UPDATE AS
DECLARE VARIABLE vCAMPO VARCHAR(64);
BEGIN
/*In then table "TCAMPOS" are the fields to validate*/
for Select CAMPO from TCAMPOS where TABLA = TPROYECTOS and ACTUALIZA = 'V' into :vCAMPO do
Begin
if (New.:vCAMPO <> Old.:vCampo) then
/*How i get dynamic New.Field1, New.Field2 on query return*/
End;
END ;
The question is : How can I put "The name of the field that the query returns me " in the above code .
Ie if the query returns me the field1 and field5 , I would put the trigger
if ( New.Field1 < > Old.Field1 ) or ( New.Field5 < > Old.Field5 ) then
There is no such feature in Firebird. You will need to create (and preferably) generate triggers that will reference all fields hard coded. If the underlying table changes or the requirements for validation, you will need to recreate the trigger to take the added or removed fields into account.

Postgresql, maintaining hierarchical data with triggers

I have adjacency list table account, with columns id, code, name, and parent_id.
To make sorting and displaying easier I added two more columns: depth, and path (materialized path). I know, postgresql has a dedicated data type for materialized path, but I'd like to use a more generic approach, not specific to postgresql. I also applied several rules to my design:
1) code can be up to 10 characters long
2) Max depth is 9; so root account can have sub accounts at maximum 8 level deep.
3) Once set, parent_id is never changed, so there's no need to move a branch of tree to another part of the tree.
4) path is an account's materialized path, which is up to 90 characters long; it is built by concatenating account codes, right padded to 10 characters long; for example, like '10000______10001______'.
So, to automatically maintain depth and path columns, I created a trigger and a trigger function for the account table:
CREATE FUNCTION public.fn_account_set_hierarchy()
RETURNS TRIGGER AS $$
DECLARE d INTEGER; p CHARACTER VARYING;
BEGIN
IF TG_OP = 'INSERT' THEN
IF NEW.parent_id IS NULL THEN
NEW.depth := 1;
NEW.path := rpad(NEW.code, 10);
ELSE
BEGIN
SELECT depth, path INTO d, p
FROM public.account
WHERE id = NEW.parent_id;
NEW.depth := d + 1;
NEW.path := p || rpad(NEW.code, 10);
END;
END IF;
ELSE
IF NEW.code IS DISTINCT FROM OLD.code THEN
UPDATE public.account
SET path = OVERLAY(path PLACING rpad(NEW.code, 10)
FROM (OLD.depth - 1) * 10 + 1 FOR 10)
WHERE SUBSTRING(path FROM (OLD.depth - 1) * 10 + 1 FOR 10) =
rpad(OLD.code, 10);
END IF;
END IF;
RETURN NEW;
END$$
LANGUAGE plpgsql
CREATE TRIGGER tg_account_set_hierarchy
BEFORE INSERT OR UPDATE ON public.account
FOR EACH ROW
EXECUTE PROCEDURE public.fn_account_set_hierarchy();
The above seems to work for INSERTs. But for UPDATEs, an error is thrown: "UPDATE statement on table 'account' expected to update 1 row(s); 0 were matched.". I have a doubt on "UPDATE public.account ..." part. Can someone help me correct the above trigger?
Well, in the above code, update part updates all records, including the record, on which the trigger was fired (concurrency execption?). That seems not to work. So I had to issue 2 different statements:
UPDATE {0}.{1} SET path = OVERLAY(path PLACING rpad(NEW.code, 10)
FROM (OLD.depth - 1) * 10 + 1 FOR 10)
WHERE SUBSTRING(path FROM (OLD.depth - 1) * 10 + 1 FOR 10) = rpad(OLD.code, 10)
AND id <> NEW.id;
NEW.path = OVERLAY(OLD.path PLACING rpad(NEW.code, 10)
FROM (OLD.depth - 1) * 10 + 1 FOR 10);