Simultaneous Use Of A Form

[niche]

I have developed a with Php and Mysql. As more people are working on it simultaneously, there is the danger that two users have the same form on the screen, and one user changes fields, while the other is then working on old information.When this latter submits, he will destroy the changes that the first user made. Is there a neat way to prevent this? Blocking certain pages, making a warning? How does that work in PHP and/or Mysql?Thank-you.

[justsomeguy]

You can keep track of the last time each field was updated, and whenever someone loads the page you can record the time they loaded. When they submit the page you can compare the time they loaded the page with the time the fields were updated so that you'll know if the fields got updated since they loaded the page.

[boen_robot]

The best I can think of is using Ajax in a "chat-like" form (or "Google Wave"-like form). Simply ping the server every second or so, and update the form if the field has changed. You won't even need a save button in this case. Other than that... I don't know.

[niche]

What about PHP Sessions, are they more trouble than they're worth?

[jeffman]

Considering what they do, PHP sessions are no trouble at all.

[justsomeguy]

The session is one place where you can store the time they loaded the page.

[niche]

I've been doing some quick reading about PHP Sessions. How do I return the UID, or will I not have the need to know the UID for someone's session?

[justsomeguy]

You can set any session variables you want, if you want to store the user ID you can. The session array is just a normal array, you can read and write to it like any other.

[niche]

Many thanks to justsomeguy, boen_robot, and Deirdre's Dad. You all helped me very much.