How rollback tran in while loop

[amit sahu20]

ALTER procedure Villas_proc_Insert_EnquiryBookingDetail
(@BId int ,@VId int,@FromDate datetime,@Todate datetime)
As
BEGIN TRAN AAA123
WHILE (@FromDate < @Todate)
BEGIN
insert into Villas_EnquiryBookingDetail(BId,VId,BookedDate)
values(@BId,@VId,@FromDate)
SET @FromDate = dateadd(day,1,@FromDate)
END
update Villas_Enquiry set status= 'Confirm' where BId= @BId
if @@error =0
BEGIN
COMMIT TRAN AAA123
END
ELSE
BEGIN
ROLLBACK TRAN AAA123
END

here VId +BookedDate are unique key in Villas_EnquiryBookingDetail table

exe Villas_proc_Insert_EnquiryBookingDetail 5,2,'03/02/2010','03/07/2010';
exe Villas_proc_Insert_EnquiryBookingDetail 5,2,'03/07/2010','03/10/2010'

how to roll back whole tran if Violation of UNIQUE KEY constraint hep pend in my procedure

[Pranay Rana]

Use Try Catch block and in catch block write statement rollback tran this may work for you easily