require() and MySQL Connection Question

[Sharif]

I have two questions:

I know you can require a page to be present with the require() function, but whats the exact difference between require() and require_once()?

Also,

Is there a way to connect to a mysql database without having to make a connection script for every page? Meaning is it possible to only connect through the first page (index.php) and stay connected throughout the entire site visit.

What are some tips to keep the database connections fast and smooth?

[HalfaBee]

The require_once() statement includes and evaluates the specified file during the execution of the script. This is a behavior similar to the require() statement, with the only difference being that if the code from a file has already been included, it will not be included again.

You can use the mysql_pconnect and it may keep the DB connection open. It all depends on how your host is setup.

It is probably best to do the connection on every page. I normally just require() a file that has all the connection stuff in it at the begining. If the connection is already open it makes no difference and if its not it connects.

HalfaBee

[Sharif]

So what's the point of using require_once()? Is it used in certain conditions?

[HalfaBee]

If you have variables defined in the required file and it can be required by other scripts the require_once only sets the variables on the first require_once() and not on the second one.

Good for defining classes and things like that.

HalfaBee