Blocking reload from inserting again

[Anon]

Hi, I'm creating a page using PHP4 and PostgreSQL. I have a form page wich calls the .php page and inserts the form info into the database. None of the fields in the form are unique in the database, that means someone can come later and type the exact same stuff and insert again. But the way that it is done now if the person presses reload on the .php page the data is inserted again. Is there a easy way to avoid that??

Thank you

[Anon]

We ran into the same problem, and resolved it by adding a SELECT query against the data that is being inserted (to see if it already exists in the D😎. If it exists in the DB the system errors out before re-inserting it.

Hope this is of some help...

Carl
[e-mail]

[Anon]

Here´s how I use to do:

The form is submitted to a php script which takes care of the sql stuff. At the end you redirect to the first, or any other page with
header("Location: filename");
(note: the php script may not do any output.)

Then it´s safe to reload the page.

/N.B

[kparker]

None of the fields in the form are unique in the database

That's the killer. But if it's really true, how do know that's it's coming from a reload rather than someone coming back 10 minutes later and re-entering the same data from scratch? And why do you care, if it's really the case that there is nothing unique about a particular entry.

Perhaps, on the other hand, you would benefit by adding some kind of unique key to your schema.

[anakya]

I had the same problem and solved it in this way (on Mysql but it must not be that different):

1) I created a new collumn im the database to store a \\"timestamp\\".

2) I inserted a new hidden field in the input form with the timestamp on it.

Then the confirmation script will get the variables and check then all against the database. If everyvariable, including timestamp, is equal to previuos posts then the function mysql_affected_rows() would return an integer greater than 0.
This would only happen on reloads as timestamp would be different everytime you submit a form.

Hope it solvres your problem.

Rgs
Kya

[Anon]

This solution solve the reload problem. But the re-submission of form data can still occur if the end user hit the back button once it has been redirected...