Limit the amount of rows added to a table

Scorpio___

Hello,

Sorry to be a pain!

How do i limit the amount of rows that can be added to a table?

I am writing an internal messaging script to allow my members to send each other messages. However, i would like to restrict the amount of messages they can send each other (eg. their message box is full after 20 messages).

Any ideas? 🙂

EDITED: Sorry guys i see how i confused you. Judging by your responses, I should of asked, how do i limit the amount of information a table can hold. My mistake.

Roger_Ramjet

Do you mean they can't send more than 20 msgs, or can't receive more than 20? Either way, you are going to have to count the existing rows and react accordingly.

obrienkev

Could you show some code? Do they enter messages via web form? Are messages stored in database?

If so use if/else statement with db query...

e.g.

$query = "SELECT * FROM table";
$result = mysql_query($query);
$num_results = mysql_num_rows($result);

if ($num_results == 20)
{
    echo 'Full';
}
else
{
// send message code
}

Hope this helps.

DoctorWho

Yeah, you are going to need messages in the database to be able to count the messages.
And a form is the best way to go about that.

I suggest you start tackling forms and getting data into the database. YOu have made a pretty big, but very conquerable, jump to the end of your project but you need to step back and take it 1 bit at a time.

First thing first, get your FORM working and sending data to the database.

That form will also need a SEND TO field so you know who is suppossed to get the message.
That way when a user logs in, you can pull his messages where USER = SEND TO.

So start working on your form.
Then start puilling up the messages base on user.

The user will also have to delete messages so that 20 Message limit can be controlled.

So second step is to delete messages the user gets.

Your above code snippet is reasonably close to what you will do in the future, when a user faces the 20 message limit.

Scorpio___

Hello,

Thanks very much for your swift feedback.

I have some experience with php. It was approx 6 months ago when i first stumbled apon my first php adventure. I knew nothing about SQL/PHP except it was tagged on the end of some webpages instead of .html! 🙂 lol

Amazed by how much more interactive your website can become by using only a handful of PHP (it makes basic html look dull!) i set myself a challenge to learn hell of a lot more.

Amongst a few (he says a few things😉 lol) other things, the only thing now i'm really stuck on now is, is it possible to limit the amount of INPUT to the SQL table so that no more than XXX entrys can be stored in a table at any given time.

Everything else like tables, extracting data, forms, i can do.

My reason behind this is with thousands of members all sending messages to each other, how large will this table get if its not limited in some way?

I would like to limit the amount of data input into the table to say, 20 messages in total per member. I'm only using 1 table for messages with an ISREAD column for read/unread status.

I hope this makes my situation a bit clearer to understand! 🙂

Thank you for all your help.

Heres my websites progression so far for anyone thats interested.
http://www.swindonchat.co.uk

(If posting urls here is not allowed, let me know and i will remove it. It's intended only as an example of my knowledge and not as spam.)

Scorpio___

Hello,

Ok i got it.

In plain english...

if ($action == "sendmessage")
{
a) run a sql COUNT on the messages table make sure theres no more than 20 messages stored
b) IF theres room, submit the form and INSERT info to the database
c) ECHO confirmation to sender
d) ELSE ECHO mail cannot be delivered
}

Works fine. 🙂

superwormy

What 'Scorpio' said is correct.

You don't want to actually limit the number of records in the table, you want to check each time a user tries to send a message and only allow them to post/send the message if they have sent/recieved/whatever less than 20 already.

Roger_Ramjet

I would just suggest that you also inform the intended recipient that someone could not send a message because the mailbox is full. Just to improve the user-experience.

One thing, if you are not stuck for disk space then do not worry about the database table growing. Mysql can handle databases and tables with millions of rows and gigs of data.