获取错误“回滚事务请求没有相应的开始事务”

Question

I am trying to create a trigger and for some reason the second if statement breaks my code.

If I delete the second if statement the code will work. The error that I am getting is:

The rollback transaction request has no corresponding begin transaction

My code:

create trigger insertemployee 
on jobinsailing 
after insert 
as 

BEGIN TRANSACTION   

declare @sailingID        int, 
        @employeeID       char(9), 
        @jobTitle         varchar(10), 
        @sailingStartDate date, 
        @sailingEndDate   date 

select @sailingId = inserted.sailingid, 
       @employeeID = inserted.employeeid, 
       @jobTitle = inserted.jobtitle, 
       @sailingStartDate = sailing.leavingtime, 
       @sailingEndDate = sailing.returntime 
from   inserted 
       inner join sailing 
               on inserted.sailingid = sailing.sailingid 

if exists(select employeeid 
          from   sailing 
                 inner join jobinsailing 
                         on sailing.sailingid = jobinsailing.sailingid 
          where  ( @sailingStartDate <= returntime ) 
                 and ( leavingtime <= @sailingEndDate ) 
                 and employeeid = @employeeID) rollback TRANSACTION; 


else if exists((select sailing.sailingid 
          from   sailing 
                 inner join jobinsailing 
                         on jobinsailing.sailingid = sailing.sailingid 
          where  Datediff(day, @sailingStartDate, sailing.leavingtime) <= 4 
                  or Datediff(day, @sailingEndDate,sailing.leavingtime) <= 4 
                  or Datediff(day, @sailingStartDate,sailing.returntime) <= 4 
                  or Datediff(day, @sailingEndDate,sailing.returntime) <= 4
                  ))  rollback TRANSACTION;

COMMIT TRANSACTION

Answer 1

Conditional Insert

What you are trying to achieve is to conditionally insert records into a table using a trigger.

This is generally a bad approach. Your code (Stored Procedures and/or business tier code) should determine if the record should be inserted first before inserting it. Triggers are not the best tool for this - they are meant to allow you to enforce complex constraints.

Assuming that you must use triggers, then I suggest you use INSTEAD OF triggers. They are designed to override the default insert process that normally occurs and allow you to insert (or not insert) data, rather than having to rollback transactions.

Multi Row Insert

As @DaleBurrell has pointed out, trigger is executed once per insert operation and inserted table can contain multiple rows. It is best practice to code your triggers such that they allow multi row operations but you can also enforce single row operations by adding this line to the top of your trigger IF (ROWCOUNT_BIG() > 1) ROLLBACK .

Further reading

• https://docs.microsoft.com/en-us/sql/t-sql/statements/create-trigger-transact-sql?view=sql-server-2017
• https://www.brentozar.com/archive/2018/02/creating-insert-triggers-silently-ignore-data-dont-want/
• http://www.sqlservertutorial.net/sql-server-triggers/sql-server-instead-of-trigger/