I am using PostgreSQL 14.5
I have a beneficiaries table where people are registered and I have BEFORE INSERT trigger function that generates a unique ID based on their location (if Paris - PAR-001, if London - LON-004, etc) and it works.
But the problem is, lots of records are inserted before writing this function, and since the function is triggered BEFORE INSERT I can't have the IDs for them.
I have seen the documentation and didn't find how to trigger the function for previous records
Can I manually trigger this function for all records once or any other solution?
Add an additional trigger like this:
CREATE TRIGGER temp BEFORE UPDATE ON tab
FOR EACH ROW WHEN (OLD.id IS NULL)
EXECUTE FUNCTION your_trigger_func();
The trigger function is the one you use in your BEFORE INSERT trigger. Then update all these rows:
UPDATE tab SET id = id WHERE id IS NULL;
You can drop the trigger when you are done.
You can perform the update in batches and run VACUUM on the table in between, to avoid bloat by a single massive update.
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.
Interbase, Sql, trigger. Can't really understand how to write a trigger of this kind: I have several tables. Each one has a document type, status and an unique number. One table in which i wish to create a trigger is a table that holds a file i post, a status of posting, a doctype corresponding to a table and a unique number linking to a record in the corresponding table. I want to change document status in the corresponding table based on the unique number to a certain status depending on the post result (status) that i change after posting. How can I do it?
Trigger T1 will be executed after update on TABLE1.
Trigger checks if TABLE1.StatusOfPosting changed to some value and depending on result updates TABLE2.DocumentStatus.
Depending on bussienes logic, maybe you will need and BEFORE DELETE trigger.
CREATE TRIGGER T1 FOR TABLE1 AFTER UPDATE POSITION 0
AS
BEGIN
IF (NEW.StatusOfPosting <> OLD.StatusOfPosting and NEW.StatusOfPosting=1) THEN
UPDATE TABLE2
SET TABLE2.DocumentStatus=1
WHERE TABLE2.UniqueNumber = TABLE1.UniqueNumber;
END
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 am attempting to setup a Trigger in my Oracle Database that fires every time a record is UPDATE'd in Table1. When the trigger executes (after?), I want to copy/insert the :old record values for all fields in the record which was updated into a HistoryTable. The only difference between the 2 tables is the inclusion of a [Table1_ID] field to reference all history records for that particular Table1.[ID]:
[Table1] - [ID][col1][col2][col3][etc.]
[HistoryTable] - [ID][Table1_ID][col1][col2][col3][etc.]
Does anyone know how to set this up? I've attempt to script it as shown below with no luck thus far, and haven't figured out how to specify the action exactly within the TOAD gui. I've already got a Sequence/Trigger pair in place so that the [ID] field for HistoryTable is auto-incremented each time a new record is inserted.
CREATE OR REPLACE TRIGGER SCHEMA1.ITEM_UPDATED_TRG
AFTER UPDATE ON TABLE1
FOR EACH ROW
DECLARE
BEGIN
INSERT INTO SCHEMA1.HISTORYTABLE (Table1_ID, col1, col2, col3, etc.)
VALUES (:OLD.ID, :OLD.col1, :OLD.col2, :OLD.col3, :OLD.etc);
END;
ShOW ERRORS;
Output window comes up with Warning: compiled but with compilation errors - No errors....?
I have written a Trigger which is transferring a record from a table members_new to members_old. The Function of trigger is to insert a record into members_old on after insert in members_new. So suppose a record is getting inserted into a members_new like
nMmbID nMmbName nMmbAdd
1 Abhi Bangalore
This record will get inserted into members_old with the same data structure of the table
My trigger is like :
create trigger add_new_record
after
insert on members_new
for each row
INSERT INTO `test`.`members_old`
(
`nMmbID`,
`nMmbName`,
`nMmbAdd`
)
(
SELECT
`members_new`.`nMmbID`,
`members_new`.`nMmbName`,
`members_new`.`nMmbAdd`
FROM `test`.`members_new`
where nMmbID = (select max(nMmbID) from `test`.`members_new` // written to read the last record from the members_new and stop duplication on the members_old , also this will reduce the chances of any error . )
)
This trigger is working for now , but my confusion is that what will happen if a multiple insertion is happening at one instance of time.
Will it reduce the performance?
Will I face deadlock condition ever in any case as my members_old have FKs?
If any better solution for this situation is there, please give limelight on that
From the manual:
You can refer to columns in the subject table (the table associated with the trigger) by using the aliases OLD and NEW. OLD.col_name refers to a column of an existing row before it is updated or deleted. NEW.col_name refers to the column of a new row to be inserted or an existing row after it is updated.
create trigger add_new_record
after
insert on members_new
for each row
INSERT INTO `test`.`members_old`
SET
`nMmbID` = NEW.nMmbID,
`nMmbName` = NEW.nMmbName,
`nMmbAdd` = NEW.nMmbAdd;
And you will have no problem with deadlocks or whatever. Also it should be much faster, because you don't have to read the max value before (which is also unsecure and might lead to compromised data). Read about isolation levels and transactions if you're interested why...