Question

I’ve got an old framework 1.1 project with the following problem: if user submits a page then in database duplicated records might appear. This error repeats often but is not consistent: in most cases there are no duplicated entries but in some cases there can be upto 4 of them. We disable submit button with JavaScript after first submission.

May be this would be helpful: there is a session object used to store user inputs (which are submitted).

Any scenarios you can think of why duplicated records can happen?

Many thanks

Answer 1

Finally I found that some mobile browsers ignored JavaScript that disabled submission button and users managed to resubmit form multiple times.

The easiest (?) solution to this is the following:

Create a table “SubmissionTokens” in database with two fields: Token (uniqueidentifier), DateCreated (DateTime). Then, when page with submission form loads, add a token to database and save “id” value in a hidden field on the same page. When user submits the form then read token from the hidden field and see if token exists in table SubmissionTokens. If it does exist then insert a new record with form data in the database and delete the token from SubmissionTokens. You can also use DateCreate field to expire tokens.

At work I implemented a bit different solution and just look for duplicated records in the database before inserting a new record. But this is because there is a specific requirement that user must be able to resubmit form if he clicks “back” in browser. In this case the SubmissionToken is already deleted and the first solution wouldn’t work.