Is this a good way to add transaction to sql ? - sql

Question

Is this a good way to add TRANSACTION to my code. I have to first update my code and if it fails then insert should also not work. Have a look please if it's a correct way or not. If not then please improve.
Begin Transaction[Transaction1]
Begin Try
IF(#ServiceInfoToJobStatus = 1)
Update ServiceInfo
Set ServiceInfoToJobStatus= 0 --To set all current jobs to prior because one person cannot have many jobs selected as current
Where #ServiceInfoToJobStatus = 1 AND ServiceInfo.fk_PersonalInfo_ServiceInfo_PID= #fk_PersonalInfo_ServiceInfo_PID
Set #ServiceInfoEntryDateTime= (Select GetDate())
Insert into dbo.ServiceInfo
(
ServiceInfoInitialDesignation,
ServiceInfoInitialBPS,
fk_Districts_ServiceInfo_InitialDistrictID,
ServiceInfoJobStatus,
ServiceInfoFromDate,
ServiceInfoDepartment,
fk_PersonalInfo_ServiceInfo_PID,
ServiceInfoServiceType ,
ServiceInfoOffice ,
ServiceInfoCadre ,
fk_WebUsers_ServiceInfo_UserID,
ServiceInfoEntryDateTime,
ServiceInfoToDesignation ,
ServiceInfoToBPS ,
fk_Districts_ServiceInfo_ToDistrictID ,
ServiceInfoToJobStatus ,
ServiceInfoToDate ,
ServiceInfoToDepartment ,
ServiceInfoToServiceType ,
ServiceInfoToOffice ,
ServiceInfoToCadre
)
Values
(
#ServiceInfoInitialDesignation,
#ServiceInfoInitialBPS,
#fk_Districts_ServiceInfo_InitialDistrictID,
#ServiceInfoJobStatus,
#ServiceInfoFromDate,
#ServiceInfoDepartment,
#fk_PersonalInfo_ServiceInfo_PID,
#ServiceInfoServiceType ,
#ServiceInfoOffice ,
#ServiceInfoCadre ,
#fk_WebUsers_ServiceInfo_UserID,
Convert(varchar, #ServiceInfoEntryDateTime, 113),
#ServiceInfoToDesignation ,
#ServiceInfoToBPS ,
#fk_Districts_ServiceInfo_ToDistrictID ,
#ServiceInfoToJobStatus ,
#ServiceInfoToDate ,
#ServiceInfoToDepartment ,
#ServiceInfoToServiceType ,
#ServiceInfoToOffice ,
#ServiceInfoToCadre
)
Set #ReturnStatus = 1
Commit Transaction[Transaction1]
End Try
Begin Catch
ROLLBACK Transaction[Transaction1]
Set #ReturnStatus= 0
Set #ReturnStatusMessage= (Select ERROR_MESSAGE())
End Catch

Answer 1

It is recommended to use add transaction (try/catch block) if the code updates or inserts data in to the table. In your case the answer is pretty yes. But in your transaction block , there is no way to recognize whether the data insert / update completed.
I would use following syntax with ##error added.
BEGIN TRY
BEGIN TRAN
//YOUR CODE
IF ##ERROR = 0
BEGIN
COMMIT TRAN;
END
END TRY
BEGIN CATCH
SELECT ##ERROR AS ERROR
ROLLBACK TRAN;
END CATCH

Answer 2

For me it is unclear what update fails means (error or no rows updated), but it does not matter much, as you can test for both pretty easy:
DECLARE #UpdateErrorNo INT
DECLARE #UpdateCount INT
DECLARE #InsertErrorNo INT
Begin Transaction[Transaction1]
Begin Try
IF(#ServiceInfoToJobStatus = 1)
Update ServiceInfo
Set ServiceInfoToJobStatus= 0 --To set all current jobs to prior because one person cannot have many jobs selected as current
Where #ServiceInfoToJobStatus = 1 AND ServiceInfo.fk_PersonalInfo_ServiceInfo_PID= #fk_PersonalInfo_ServiceInfo_PID
SET #UpdateErrorNo = ##ERROR
SET #UpdateCount = ##ROWCOUNT
Set #ServiceInfoEntryDateTime= (Select GetDate())
Insert into dbo.ServiceInfo
(
-- skipped for readability
)
Values
(
-- skipped for readability
)
SET #InsertErrorNo = ##ERROR
Set #ReturnStatus = 1
Commit Transaction[Transaction1]
End Try
Begin Catch
ROLLBACK Transaction[Transaction1]
Set #ReturnStatus= 0
Set #ReturnStatusMessage= (Select ERROR_MESSAGE())
End Catch
-- here you can read `#UpdateErrorNo`, `#InsertErrorNo` to check for errors
The tricky part is that ##ERROR is set after each statement, so if you have a case like this (no try/catch):
BEGIN TRAN
INSERT ... -- fails
UPDATE ... -- success
-- ##ERROR will not show that it is a failure
COMMIT
it might lead to unexpected results.

Answer 3

declare #cdt datetime = getdate()
begin try
begin transaction
Update dbo.ServiceInfo
Set ServiceInfoToJobStatus= 0 --To set all current jobs to prior because one person cannot have many jobs selected as current
Where #ServiceInfoToJobStatus = 1
AND fk_PersonalInfo_ServiceInfo_PID= #fk_PersonalInfo_ServiceInfo_PID
Insert into dbo.ServiceInfo
(
ServiceInfoInitialDesignation,
ServiceInfoInitialBPS,
fk_Districts_ServiceInfo_InitialDistrictID,
ServiceInfoJobStatus,
ServiceInfoFromDate,
ServiceInfoDepartment,
fk_PersonalInfo_ServiceInfo_PID,
ServiceInfoServiceType ,
ServiceInfoOffice ,
ServiceInfoCadre ,
fk_WebUsers_ServiceInfo_UserID,
ServiceInfoEntryDateTime,
ServiceInfoToDesignation ,
ServiceInfoToBPS ,
fk_Districts_ServiceInfo_ToDistrictID ,
ServiceInfoToJobStatus ,
ServiceInfoToDate ,
ServiceInfoToDepartment ,
ServiceInfoToServiceType ,
ServiceInfoToOffice ,
ServiceInfoToCadre
)
Values
(
#ServiceInfoInitialDesignation,
#ServiceInfoInitialBPS,
#fk_Districts_ServiceInfo_InitialDistrictID,
#ServiceInfoJobStatus,
#ServiceInfoFromDate,
#ServiceInfoDepartment,
#fk_PersonalInfo_ServiceInfo_PID,
#ServiceInfoServiceType ,
#ServiceInfoOffice ,
#ServiceInfoCadre ,
#fk_WebUsers_ServiceInfo_UserID,
Convert(varchar, #cdt, 113),
#ServiceInfoToDesignation ,
#ServiceInfoToBPS ,
#fk_Districts_ServiceInfo_ToDistrictID ,
#ServiceInfoToJobStatus ,
#ServiceInfoToDate ,
#ServiceInfoToDepartment ,
#ServiceInfoToServiceType ,
#ServiceInfoToOffice ,
#ServiceInfoToCadre
)
return ...
commit transaction
end try
begin catch
if(##TRANCOUNT > 0)
rollback transaction
return ...
end catch

Answer 4

That's what I use:
Begin Try
Begin Tran
-- Do your thing... some DML statements
Commit Tran
End Try
Begin Catch
If ( ##TranCount > 0 )
Rollback Tran
End Catch