I am trying to create a trigger that whenever you insert values inside a table called hotel, it takes some values from the field and inserts it inside another table called Restaurant.
My Hotel_ID is in sequence so I don't really give its value when I am using the insert statement to insert values inside the hotel table. Which creates problems for the restaurant table as it sets the value of Hotel_ID to null. I know in the insert statement I can just add the sequence name so that it works but the thing is, later on I have to convert my tables into APEX forms and with them, you can't insert the ID at all.
Anyway, here is my trigger that is basically supposed to take values from some fields of Hotel table and insert them into the Restaurant table:-
create or replace TRIGGER HOTELREST BEFORE INSERT ON HOTEL
FOR EACH ROW
BEGIN
IF INSERTING THEN
INSERT INTO RESTAURANT(CITY,ADDRESS,HOTEL_ID)
VALUES (:NEW.CITY,:NEW.ADDRESS,:NEW.HOTEL_ID);
END IF;
END;
Although the values of City and address get inserted inside the restaurant table, the value of hotel_id doesn't. Here is my insert statement for hotel:
INSERT INTO HOTEL(NAME,CITY,COUNTRY,ADDRESS,RATINGS)
VALUES ('Westin','Manchester','UK',5);
Now again, before you say that I didn't give an Id of the hotel, like I said, I am using sequence so when this row gets inserted inside the hotel table, a value for Hotel_Id is automatically generated. My trigger is also supposed to add Hotel_Id in my Restaurant table but it doesn't. It remains null. What do I do?
Related
I am trying to create a trigger function, to create a new row, in a table, when a value is modified or created in another table. But the problem is that I need to insert in the other table, the primary key that provoked the trigger function.
Is there a way to do it?
Basically, when an insert or update will be done in table 1, I want to see in table 2 a new row, with one field filed with the value of the primary key of the row in table1 that provoked the trigger.
begin
INSERT INTO resultados_infocorp(id_user, Procesado)
VALUES (<PRIMARY_KEY>,false)
RETURN NEW;
End;
This is because if Procesado is false, thank to the id_user I will make some validations, but the ID of the user is necesary and I cant do it from the backend of my project, because I have many db inputs.
PD: The primary key of the new table is a sequence, this is the reason why I am not passing this arg.
CREATE TRIGGER resultados_infocorp_actualizar
AFTER INSERT OR UPDATE OF id_user, fb_id, numdocumento, numtelefono, tipolicencia, trabajoaplicativo
ON public.usuarios
FOR EACH ROW
EXECUTE PROCEDURE public.update_solicitudes_infocorp();
You have not shown the trigger definition. Still if you want the PK value then something like:
INSERT INTO resultados_infocorp(id_user, Procesado)
VALUES (NEW.pk_fld,false)
Where pk_fld is the name of your PK field. Take a look here:
https://www.postgresql.org/docs/current/plpgsql-trigger.html
for what is available to a trigger function. For the purpose of this question the important part is:
NEW
Data type RECORD; variable holding the new database row for INSERT/UPDATE operations in row-level triggers. This variable is null in statement-level triggers and for DELETE operations.
I am trying to build an order system that is able to insert a compound order that consists of multiple items and amounts. My database layout is as follows: I have an order table, containing an autoincrement id, item_id, amount and order_group_id columns. I also have an order_group table containing an autoincrement id and a person_id column. The idea is that when a person orders, one new order_group entry is created, and its id is used as the fk in the orders that the person has done.
I presume that this would normally be done in the code of the application. However, I am using postgrest to provide an API for me, which suggests creating a custom view to insert compound entries via that route. This is described here.
This is what I have so far:
CREATE FUNCTION kzc.new_order()
RETURNS TRIGGER
LANGUAGE plpgsql
AS $$
DECLARE
group_id int;
BEGIN
INSERT INTO kzc.order_group (person) VALUES (new.person) RETURNING id AS group_id;
INSERT INTO kzc."order" (item, amount, order_group) VALUES (new.item_id, new.amount, group_id);
RETURN new;
END;
$$;
CREATE TRIGGER new_order
INSTEAD OF INSERT ON kzc.new_order
FOR EACH ROW
EXECUTE FUNCTION kzc.new_order()
However, this code makes a new ordergroup for every order that is in the compound insert. How can I make it so that my code only makes one new ordergroup entry and assigns its id to all orders?
Thanks in advance!
I suggest that you add an order_group_id column to the new_order view and create a sequence for it. Then create a DEFAULT value for the column:
ALTER VIEW kzc.new_order
ALTER order_group_id SET DEFAULT currval('order_group_id_seq');
Add a BEFORE INSERT trigger FOR EACH STATEMENT that just calls nextval for the sequence. The currval calls will all pick up the same generated value.
Then you have that number in your trigger and can use it as a primary key for order_group.
To avoid adding the row multiple times, use
INSERT INTO kzc.order_group (id, person)
VALUES (NEW.order_group_id, NEW.person)
ON CONFLICT (id) DO NOTHING;
I'm in trouble with the implementation of a trigger.
Assuming that I have two types:
CREATE TYPE customer_t AS OBJECT(
code INTEGER,
name VARCHAR(20),
surname VARCHAR(20),
age INTEGER);
and the type
CREATE TYPE ticket_t AS OBJECT (
price INTEGER,
cust REF customer_t
)
And then I have the associate tables:
CREATE TABLE customers OF TYPE customer_t
CREATE TABLE tickets OF TYPE ticket_t
I have to do an exercise so I have to create a trigger for ensure that a customer won't buy more than 10 tickets but, if I use command like "select count(*)" I get an error because I can't access to mutating table.
Please can anyone help me with this trigger?
EDIT:
I populated the tables as follows:
INSERT INTO custs (code, name, surname, age) values (123, 'Paolo', 'Past', 32);
and repeating the following operation ten times:
INSERT INTO tickets (price, cust) values
(4, (SELECT * FROM (SELECT REF(T) FROM custs T WHERE name = 'Paolo' AND surname = 'Past') WHERE rownum < 2))
The trigger implemented is:
create or replace
trigger check_num_ticket after insert on tickets
for each row
declare
num_ticket number;
begin
SELECT count(*) INTO num_ticket FROM tickets WHERE :new.cust = cust;
if (num_ticket >= 10) then
raise_application_error('-20099', 'no ticket available');
end if;
end;
And I get this error:
A trigger (or a user defined plsql function that is referenced in
this statement) attempted to look at (or modify) a table that was
in the middle of being modified by the statement which fired it.
You are getting the mutating table error, because you are inserting in the same table where you want to get the row count for. Imagine your insert statement inserts two rows. There is no rule which row to insert first and which last, but your trigger fires on one inserted row and wants to know how many rows are already in the table. The DBMS tells you this is undefined, as the table is currently mutating.
You need an after statement trigger instead of a before row trigger. So when the insert statement's inserts are done, you look at the table to see whether there are suddenly customers with too many rows in it.
(A great alternative is a compound trigger. It combines row and statement triggers. So in the after row section you'd remember the customers in some array/collection and in the after statement section you'd look up the table for only the remembered customers.)
I have the following table
Data --Table name
ID -- Identity column
PCode -- Postal Code
I created the following trigger:
CREATE TRIGGER Trig
ON Data
FOR INSERT
AS
BEGIN
Select * from inserted
END
And inserted the following values
INSERT INTO Data VALUES (125)
INSERT INTO Data VALUES (126)
INSERT INTO Data VALUES (127)
It shows this:
But I was expecting something like this:
After the 1st insertion, the trigger is executed -> one row is shown in the inserted table.
After the 2nd insertion, the trigger is executed -> two rows are shown in the inserted table.
After the 3rd insertion, the trigger is executed -> three rows are shown in the inserted table.
According to msdn.microsoft all the rows inserted are in this table.
How can I access the inserted table so that I can see all the expected rows and not separately?
You can not. From the Use the inserted and deleted Tables article on microsoft.com, you can read:
The inserted table stores copies of the affected rows during INSERT and UPDATE statements.
That means that the inserted table will only contain rows for the current INSERT or UPDATE statement.
If you do want to see all rows for several such INSERT or UPDATE statements, you will have to store these rows in a table you created yourself.
There are 2 table available in a trigger, the inserted and the deleted. Each update on table XXX is actually a delete row X from XXX then an insert of row X in table XXX. So the inserted inside the trigger is a copy of what got inserted. You can do a lot with a trigger, but triggers are dangerous.
For example, on a performance gig, I found a huge SP being run by a trigger, we dropped it and the database came back online. Or another example, if you do a trigger wrong to audit logins, you can down the server.
As TT mentioned, if you want to see all the inserted records then you need to change your Trigger to something like this:
CREATE TRIGGER Trig
ON Data
FOR INSERT
AS
BEGIN
Select * into "tablename"
from
(Select * from inserted) Ins
END
I have a simple trigger setup, which is used to insert records into a RentJournal table, whenever there is a record inserted in the UnitAGA table.
The RentJournal table has a primary key ID column named RentJournalID, which is auto incrementing. The UnitAGA table also has a nullable foreign key column named RentJournalID, which links each UnitAGA entry, to its corresponding entry in RentJournal table (which is inserted through the Trigger below).
Problem is that currently this Trigger is only inserting values into RentJournal table. But now I want to also fetch the ID assigned for each RentJournal entry through this Trigger, and write that into the corresponding UnitAGA record, whose insert actually triggered the Trigger in the first place. How do I do this ?
The Trigger code as of right now is this:
USE [RentDB]
GO
ALTER TRIGGER [RTS].[InsertRentJournalEntry]
ON [RTS].[UnitAGA]
AFTER INSERT
AS
BEGIN
INSERT INTO RTS.RentJournal
(UnitId, AdjustmentType, EffectiveDate, ReferenceFormNo)
SELECT
UnitId, 'AGA', EffectiveDate, ReferenceFormNo FROM inserted
END
Have a look at the INSERT logical table that is available in insert triggers:
DML triggers use the deleted and inserted logical (conceptual) tables. They are structurally similar to the table on which the trigger is defined, that is, the table on which the user action is tried. The deleted and inserted tables hold the old values or new values of the rows that may be changed by the user action. For example, to retrieve all values in the deleted table, use: SELECT * FROM deleted
http://technet.microsoft.com/en-us/library/ms189799.aspx
Then use ##IDENTITY to get the value of the identity column on your RentJournal table.
So you should be able to do something like:
update INSERTED set RentJournalID = ##IDENTITY