Application architecture

Hi, I'm new to this site and to php. As a get-my-feet-wet project, I'm writing a site-based calendar. I would like to allow users to put personal events in the calendar, then get emailed reminders.
Here's my question: can I store users' data on their PCs instead of mine, so I don't need to load up my server? Is this even a good idea, architecturally?
Can the data be stored in a text file, so they don't need to install database software? Does this design mean they have to install a client-side app (mine) to handle data-handling?
.... etc, etc..... thanks, Rob

The only way to store data on the client's computer (at least without using Java or Javascript and dealing with permissions and just confusing to most people) is to use cookies. Search the forums or read PHP.net's cookie page.

As far as if that's a good idea or not: yes and no.

Reasons it's not good:
1. Storing a lot of information in cookies probably isn't a good idea because it's slow (all that data has to be sent to the server on each HTTP request)
2. It means that the person can only access their information from their computer - although that makes it more secure
3. The server only has access to the data when the person is browsing the site, which will make email reminders difficult to send.

Reasons it's good:
1. You don't need to be as responsible for keeping the data secure.
2. People can't use up your server space with useless data.

I'm sure there are other reasons on both sides, but I'd suggest you use a database like MySQl instead.

Thank you! Especially for the pro/con explanations. I don't know how the whole client-server conversation works, and your pro/con stuff illuminated that a little for me.
Got a recommend for a resource (book, site) for these kinds of questions? Rob

So, honcho,
When you say use MySQL, you mean a server-side database, right? This calendar would go on an ISP site with potentially thousands of customers. Any idea how big a db would be with say, 50,000 entries? And what kind of processing power it would require to handle pulling data for requests? Does this seem like a light-weight app, or something that would detract from the higher-priority tasks?
Rob

For a pretty good overview (not too technical, but more detailed than your average newspaper), look at http://www.howstuffworks.com.
Cookies: http://computer.howstuffworks.com/cookie.htm
Web servers: http://computer.howstuffworks.com/web-server.htm

For a much more detailed view, try http://www.w3.org/Protocols/


Yes. See http://www.mysql.com.



I don't have any hard numbers to reference, but you should be able to find something useful about this on MySQL.com. I really doubt any calendar you create for an average ISP and its customers would be overly complicated and require all that much processing (i.e., you won't need to do any really complicated or processor intensive queries). If the ISP can handle thousands of people hitting it's website, it should have no trouble handling a comparable database load.