Cursor on a trigger - sql-server

Question

I'm using SQL Server 2008.
I have an after trigger for INSERT, UPDATE and DELETE action defined in the table. My problem is that currently my trigger inserts one record at a time and I need multiple records as for one
SELECT TOP 1 #ParentID FROM ... WHERE ID = #ID
returns multiple unique records.
(See this comment below "-- this subquery returns more than 1 value, so I need to insert in the search Audit table as many ParentIDs as it returns")
I believe I need to use cursor, but I'm not sure where exactly to declare and open cursor.
--CREATE PROCEDURE [dbo].[SP_Auditing]
-- #ID INT, #Code VARCHAR(3), #AuditType VARCHAR(10), #ParentCode VARCHAR(3) = NULL, #ParentID INT = NULL
--AS
--BEGIN
-- INSERT INTO myDB.dbo.Table1 (ID, Code, AuditType, ParentCode, ParentID)
-- VALUES(#ID, #Code, #AuditType, #ParentCode, #ParentID)
--END
GO
CREATE TRIGGER [dbo].[Tr_MyFavouriteTable_UPD_INSERT_DEL] ON [dbo].[MyFavouriteTable] AFTER INSERT, DELETE, UPDATE NOT FOR REPLICATION
AS
BEGIN
DECLARE #ID INT, #Code VARCHAR(3), #AuditType VARCHAR(10), #ParentCode VARCHAR(3), #ParentID INT SET #Code = 'DOC'
IF EXISTS (SELECT 1 FROM inserted) AND
NOT EXISTS (SELECT 1 FROM deleted)
BEGIN
SELECT TOP 1
#ID = ins.ID,
#ParentID = (
SELECT TOP 1 CAST(RIGHT(parentId,LEN(parentId) - LEN(LEFT(parentId,3))) AS INT)
FROM [MyDB].[dbo].[MyFavouriteTable] t WITH (NOLOCK)
INNER JOIN [MyDB2].[dbo].[MyView] v WITH (NOLOCK)
ON t.Id = v.ID
WHERE v.ID = #ID --284
), **-- this subquery returns more than 1 value, so I need to insert in the search Audit table as many ParentIDs as it returns**
#AuditType = 'INSERT' FROM inserted ins
IF #ID IS NOT NULL
AND
#ParentID IS NOT NULL
AND
#ParentCode IS NOT NULL
EXEC [MyDB].[dbo].SP_Auditing] #ID, #Code, #AuditType, #ParentCode, #ParentID
END
-- below is the same logic for UPDATE and DELETE actions...
The stored procedure above simply inserts data into the Audit table.

Answer 1

Never use scalar variables in triggers because insert, update, and delete may affect multiple rows. As to your trigger, try something like this.
CREATE TRIGGER [dbo].[Tr_MyFavouriteTable_UPD_INSERT_DEL]
ON [dbo].[MyFavouriteTable] AFTER INSERT, DELETE, UPDATE
NOT FOR REPLICATION
AS
BEGIN
;with act as (
select isnull(i.id,d.id) id, --either deleted or inserted is not null
case when i.id is not null and d.id is not null then 'update'
when i.id is not null then 'insert'
else 'delete' end auditType
from inserted i full outer join deleted d on i.id = d.id
),
audit_cte as (
SELECT act.id, 'DOC' Code,
CAST(RIGHT(parentId,LEN(parentId) - LEN(LEFT(parentId,3))) AS INT) parentid,
act.auditType, 'parentcode' parentCode
FROM [MyDB].[dbo].[MyFavouriteTable] t WITH (NOLOCK)
INNER JOIN [MyDB2].[dbo].[MyView] v WITH (NOLOCK) ON t.Id = v.ID
inner join act on act.id = t.id
)
insert myDB.dbo.Table1 (ID, Code, AuditType, ParentCode, ParentID)
select id,code,AuditType, ParentCode, ParentID
from audit_cte
where parentCode is not null and parentid is not null
end

Answer 2

Why do you need to get the records one by one? From my understanding you want to keep the log.
IF EXISTS (SELECT 1 FROM inserted) AND
NOT EXISTS (SELECT 1 FROM deleted)
BEGIN
INSERT INTO [Your_Log_Table]
SELECT
ins.ID, [Code],'INSERT',[PrentCode],
(SELECT TOP 1 CAST(RIGHT(parentId,LEN(parentId) -
LEN(LEFT(parentId,3))) AS INT)
FROM [MyDB].[dbo].[MyFavouriteTable] t WITH (NOLOCK)
INNER JOIN [MyDB2].[dbo].[MyView] v WITH (NOLOCK)
ON t.Id = v.ID
WHERE v.ID = ins.ID --284
)
FROM inserted ins
END

Answer 3

See Alex Kudryashev's answer. I needed to tweak a little his logic to sort out duplicate records with the same ParentIDs for the insertion into the Audit table. I added one more cte just below Alex's cte_Audit as follows
CREATE TRIGGER [dbo].[Tr_MyFavouriteTable_UPD_INSERT_DEL]
ON [dbo].[MyFavouriteTable] AFTER INSERT, DELETE, UPDATE
NOT FOR REPLICATION
AS
BEGIN
;with act as (
select isnull(i.id,d.id) id, --either deleted or inserted is not null
case when i.id is not null and d.id is not null then 'update'
when i.id is not null then 'insert'
else 'delete' end auditType
from inserted i full outer join deleted d on i.id = d.id
),
audit_cte as (
SELECT act.id, 'DOC' Code,
CAST(RIGHT(parentId,LEN(parentId) - LEN(LEFT(parentId,3))) AS INT) parentid,
act.auditType, 'parentcode' parentCode
FROM [MyDB].[dbo].[MyFavouriteTable] t WITH (NOLOCK)
INNER JOIN [MyDB2].[dbo].[MyView] v WITH (NOLOCK) ON t.Id = v.ID
inner join act on act.id = t.id
)
insert myDB.dbo.Table1 (ID, Code, AuditType, ParentCode, ParentID)
select id,code,AuditType, ParentCode, ParentID
from audit_cte
where parentCode is not null and parentid is not null
,CTE_dupsCleanup AS (
SELECT DISTINCT
Code,
Id,
AuditType,
ParentCode,
ParentId,
-- ROW_NUMBER() OVER(PARTITION BY ParentId, ParentCode, AuditType ORDER BY ParentId) AS Rn
FROM AUDIT_CTE
WHERE ParentCode IS NOT NULL
AND ParentId IS NOT NULL )
Then using Rn = 1 inserted only unique records into the Auidt table. Like this:
INSERT [ISSearch].[dbo].[SearchAudit] (Code, ID, AuditType, ParentCode, ParentID)
SELECT
Code,
ID,
AuditType,
ParentCode,
ParentId
FROM CTE_dupsCleanup
-- WHERE Rn = 1
END