Shell Programming and Scripting

When do PHP variables/objects vanish?
Say, I have a database structure in index.php, I called connect(). Then I sent the user another page, say index2.php. Should I create a fresh database structure and call connect() again, or is there a way around this?

They won't. Really. Unless you purposely unset() them.

It really depends on how you "send". If you just require("index2.php") from within index.php, then variables in index.php will be available to index2.php. They won't vanish.

What do you mean by a "database structure"? Some table data fetched? or the database /statement handle itself?

If the "send" you meant is by means of an HTTP/meta redirect, you may always try to save some array or even objects into session. However, certain types such as database handles are not serializable and thus cannot be put in session. Therefore, you need to open a connection to the database for each HTTP request in this case.

Try pconnect() (which means persistent connect). This function tries to pool connections and if there are some avail open connections it does not make new one each time but selects from the pool.

I always avoid pconnect() because for mysql it is known to multiplex multiple connections to the same host for two databases. In the past I found this a harsh way. Wanting to open two connections to copy rows from one database to the next, and at the end everything was messed up badly.

Although the database connection is persistent, but on every page you still need to call connect to get the database handle, isn't it?

You are totally right

Yes, but the connectin is not dropped/created each time

No, I mean this: I have index.php, some variables in it, and a URL to another page, say index2.php. When user clicks index2.php, previous variables no longer exists, right?

I mean a PHP class that handles all SQL stuff. Has functions such as connect(), close(), fetchrow(), etc.

So, that can't be helped...
OK, thanks for the help!

Right

Check out http://www.kitebird.com/articles/peardb.html, this may help you