AFTER INSERT trigger causes query execution to hang up - tsql

Question

In a ms sql database I have a table named combo where multiple inserts, updates and deletes can happen (as well as single, of course). In another table named migrimi_temp I keep track of these changes in the form of queries (query that would have to be executed in mysql to achieve the same result).
For example, if a delete query is performed for all rows where id > 50, the trigger should activate to store the following query into the log table:
DELETE FROM combo where id > 50;
Therefore this one delete query in the combo table would result in one row in the log table.
But if instead I have an insert query inserting 2 rows, a trigger should activate to store each insert into the log table. So this one insert query in the combo table would result into 2 new rows in the log table.
I intend to handle insert, update and delete actions into separated triggers. I had managed to write triggers for single row insert / update/ delete. Then it occurred to me that multiple actions might be performed too.
This is my attempt to handle the case of multiple inserts in one single query. I resorted to using cursors after not being able to adapt the initial trigger without a cursor. The trigger is executed successfully, but when I perform an insert (single or multiple rows) the execution hangs up indefinitely, or at least longer than reasonable .
USE [migrimi_test]
GO
/****** Object: Trigger [dbo].[c_combo] Script Date: 12/11/2017 5:33:46 PM ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
create TRIGGER [dbo].[u_combo]
ON [migrimi_test].[dbo].[combo]
AFTER INSERT
AS
BEGIN
SET NOCOUNT ON
DECLARE #c_id INT;
DECLARE #c_name nvarchar(100);
DECLARE #c_duration int;
DECLARE #c_isavailable INT;
DECLARE c CURSOR FOR
SELECT id, name, duration, isvisible FROM inserted
OPEN c
FETCH NEXT FROM c INTO #c_id, #c_name, #c_duration, #c_isavailable
WHILE ##FETCH_STATUS = 0
INSERT INTO [migrimi_temp].[dbo].[sql_query] (query)
VALUES ('INSERT INTO combo (id, name, duration, value, isavailable, createdAt, updatedAt) values ('+CAST(#c_id as nvarchar(50))+', '+'"'+#c_name+'"'+',
'+CAST(#c_duration as nvarchar(50))+', 1, '+CAST(#c_isavailable as nvarchar(50))+', Now(), Now());' )
FETCH NEXT FROM c INTO #c_id, #c_name, #c_duration, #c_isavailable
CLOSE c
END
DEALLOCATE c
GO
SQL server version is 2012. OS is windows server 2008 (though I doubt that is relevant). I was based mainly on these two resources: https://social.msdn.microsoft.com/Forums/sqlserver/en-US/40f5635c-9034-4e9b-8fd5-c02cec44ce86/how-to-let-trigger-act-for-each-row?forum=sqlgetstarted
and How can I get a trigger to fire on each inserted row during an INSERT INTO Table (etc) SELECT * FROM Table2?
This is part of a larger idea I am trying to accomplish, and until 2 days ago I was totally unfamiliar with triggers. I am trying to balance learning with accomplishing in reasonable amounts of time, but not doing so great

Answer 1

Cursors are notoriously slow in SQL Server.
Instead of using a cursor to loop over the inserted table, you can use insert...select which is a set based approach. It is much faster and is the recommended way to work in SQL:
CREATE TRIGGER [dbo].[u_combo]
ON [migrimi_test].[dbo].[combo]
AFTER INSERT
AS
BEGIN
INSERT INTO [migrimi_temp].[dbo].[sql_query] (query)
SELECT 'INSERT INTO combo (id, name, duration, value, isavailable, createdAt, updatedAt) values ('+CAST(id as nvarchar(50))+', "'+ name +'",
'+ CAST(duration as nvarchar(50)) +', 1, '+ CAST(isvisible as nvarchar(50))+ ', Now(), Now());'
FROM inserted
END
GO