Sql-server – Database structure

While not a good design, it is doable. You'll need to put logic in the trigger so it causes the code to only be executed when the correct application is connected.

Create trigger... 
As
    If app_name() = 'something' 
    begin 
        put code here 
    end

Depending on how up-to-date, you want the reports to be, you can use

1. Log shipping : with delay of log restore on secondary and choosing the secondary to be read only with disconnect users when restoring the log. This will allow you to have read from secondary server.

   you just have to balance between the restore frequency on the secondary.

   log shipping will be much more efficient as compared to your approach and it works out of the box and you can even monitor it. Plus you get a warm standby server which will act as a DR if the primary goes down (cavet is -- depending on the frequency of your log restores, there will be some amount of dataloss)

2. Transactional replication : if your main database is not undergoing schema changes and you want near-to-real time reporting, you can use T-rep. Just make sure that you are replicating ONLY objects that are required for your reports. The initial snapshot will have some penalty on your main database.

As a side note, depending on what version and edition of SQL server you are using, in 2012 and up, you can leverage AlwaysON with readable secondaries to offload reporting to the secondary server.

Let me know if you want any further clarification and I will be happy to help you out.

Edit:

it runs perfect for the 1st time but next time if gives me error:

The reason might be because the full backup's FirstLSN wont be matching the Differential backup's DifferentialBaseLSN ==> meaning if the values do not match, then you would need a full backup followed by a diff.