I am creating a control table in a PostgreSQL database, this table should register the query that fired a trigger in a specific table. For instance
if I do
insert into employees('bob');
I would like to be able to capture the string 'insert into employees('bob');' inside a trigger associated with employees table. It doesn't matter if the trigger is before or after.
Use the function current_query() in the trigger function.
insert into control_table(query_text)
select current_query();
The trigger should be for each statement.
Related
So I am new to using procedures and triggers and it is really confusing me
I have used temporal tables and want to basically create a history table of records inserted,updated or deleted.
Infact I have created my history table and works fine when I use this trigger sql
DROP TRIGGER if exists versioning_trigger on mytable;
CREATE TRIGGER versioning_trigger BEFORE INSERT OR UPDATE OR DELETE ON mytable FOR EACH ROW EXECUTE PROCEDURE versioning('sys_period', 'table_history', true);
This creates records of the rows updated or deleted,precisely copies the old row record from mytable into table_history table and updates the record in mytable.But I want to insert the updated record from mytable to table_history also so that it has records of all types('current active record'and 'record before updation').Also insert some other fields in table_history when the trigger is executed.
I want to ask
How is it possible to have different trigger events(BEFORE or AFTER) together in one CREATE TRIGGER query in temporal_tables?
Is it possible to insert new field values in table_history on trigger execution? How can I accomplish this?
https://www.postgresql.org/docs/current/static/plpgsql-trigger.html
A trigger procedure is created with the CREATE FUNCTION command,
declaring it as a function with no arguments and a return type of
trigger
and also
same trigger can't fire both before and after event - just create two triggers if you really need it
https://www.postgresql.org/docs/current/static/sql-createtrigger.html
Determines whether the function is called before, after, or instead of
the event.
use NEW instead of OLD for new values
https://www.postgresql.org/docs/current/static/plpgsql-trigger.html
NEW
Data type RECORD; variable holding the new database row for
INSERT/UPDATE operations in row-level triggers. This variable is
unassigned in statement-level triggers and for DELETE operations.
I know that in plpgsql if one would want to refer to the new inserted row, you can use "NEW".
How can I do this in T-SQL (transact sql)?
The following is the trigger I am trying to create:
CREATE Trigger setAlertId on rules_table
FOR INSERT AS
DECLARE #max_id integer
SELECT #max_id = (select max(AlertId) from rules_table)
NEW.AlertId = #max_id+1
END
GO
I get the error message:
Incorrect syntax near 'NEW'
Thanks.
inserted and deleted pseudo tables:
DML trigger statements use two special tables: the deleted table and the inserted tables. SQL Server automatically creates and manages these tables. You can use these temporary, memory-resident tables to test the effects of certain data modifications and to set conditions for DML trigger actions. You cannot directly modify the data in the tables
In your case why dont you use an identity on the alertid field that increments itself?
If you want to do it in your trigger you will need to select your primary key from inserted and then do an update on rules tables.
I am new to the use of Database triggers so I want to get pointed in the right direction here. I would like to make a trigger to execute on 'insert' of new Invoice or 'Update' of 'BalanceDue' of my Invoice table to take the VendorID in Invoices, Grab the Vendor row in the Vendors table and move some data from that row to another table for ShippingLabels. This is what I got so far but Im kinda at a loss for where to go from here.
CREATE TRIGGER trSetShippingLabels
ON tblInvoices
AFTER Insert, Update
AS
INSERT INTO tblShippingLabels
SELECT VendorName, VendorAddress, VendorCity, VendorState, VendorZipCode
FROM tblVendors
JOIN tblInvoices i on i.VendorID = Vendors.VendorID
You're pretty close. You just need to use the special "inserted" table within your trigger. This table is accessible within triggers (or in conjunction with the output clause), and holds all the data inserted by the last statement executed against the relevant permanent table. There is also a corresponding "deleted" table if you wanted to remove some data in a trigger.
CREATE TRIGGER trSetShippingLabels
ON tblInvoices
AFTER Insert,Update
AS
INSERT INTO tblShippingLabels
SELECT VendorName, VendorAddress, VendorCity, VendorState, VendorZipCode
FROM Vendors
JOIN Inserted i on i.VendorID = Vendors.VendorID
I have a trigger with before insert option and inside the trigger I insert the data to the same table. How would SQL handle this kind of issues as this lead to creating infinite triggers.
For Example:
Create trigger trigger_name on Employee
before insert
as
insert on table Employee values(1001, 'chas');
go
Thanks for the help
I want to create a trigger, somehow like this:
CREATE TRIGGER foo
AFTER UPDATE OR INSERT ON bar
FOR EACH ROW EXECUTE PROCEDURE baz(NEW.id);
The part with NEW.id doesn't work. How can I send values from the changed row (id for instance) to the trigger-function.
The trigger function (procedure) knows NEW and OLD automatically. No need to pass those as parameters.
Read more in the chapter on Trigger Procedures in the manual:
When a PL/pgSQL function is called as a trigger, several special
variables are created automatically in the top-level block. They are:
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.