Wrox asignment trouble

JeePee

Hi, i have been studying Beginning PHP, Apache, ... and all went smoothly uptill the asignment in chapter 3 that sais "Create a php program that prints the lead actor and director for each movie in the database"

I tried to do that with a mysql link but i figured that wasn't possible because of the makeup of the main table. So i eventualy just went ahead and looked how it was suposed to be done.
The problem is; some elements in the "answer code" are not covered in the preceding chapters.

Below is a piece of the code, the thing that i can't figure out about this and similiar blocks is the ($leadactor) "argument?" in the function. Because the variable isn't mentioned anywhere else in the script nor does it match a field name. Passing arguments hasn't been covered so my understanding of it could be limited.

Anyone here that can demistify this?

//create function to get lead actor
function_ get_leadactor($leadactor) {
global $actorname
$query2="SELECT people_fullname FROM people
WHERE people.people_id=$lead_actor";
$results=mysql_query($query2) or die(mysql_error());
$rows=mysql_fetch_array($results);
extract ($rows);
$actorname=people_fullname;
}

Installer

It looks like a typo. "$lead_actor" in the query should be "$leadactor".

Roger_Ramjet

Can't really see the need for extract($rows) here ??
At a best it's 1 unneccessary program step cos $actorname=$rows['people_fullname']; does exactly what is needed.
At worst, extract() is a problem waiting to happen: it fails when the array contains NULL values (a frequent occurance in query results), when the key is not a valid php var name (but is a valid mysql column names), and can overwrite existing values when register globals are ON.

Surprised by all this as WROX are generally a quality publisher, but this looks like one of those 'cash in on the php craze' books full of outdated and faulty code.

dalecosp

Heh, let's be careful. Most of the authors (if this is the book I'm thinking we mean) are members here.

From what I remember, one of the big problems they had was that the copy secretaries at the publisher used MS Word to typeset their code. Big mistake....

JeePee

Ok, i won't take theire example to serious then. The rest of the code has been good by the way, this is the first script that is out of place. I could have figured it since there were other errors that were obvious to me, but it's hard to figure out what's good and what not as a beginner :queasy:

Roger_Ramjet

Well dale, I hope I've not upset anyone. As I said, WROX are one of the good publishers and it was a surprise to see this problem. But you are right, I should not have jumped to conclusions.

I stand by my criticism of the extract() issue though. I suppose they are using it here to introduce it to the reader, rather than because it is needed. If they have explained it's uses and limitations in the text then OK, but then they should have used an example that needed it.

dalecosp

Hard to say who might be offended. I think that they got rushed into publication, which might support the "jump on the craze" theory. Me, I'm not a writer, per se; I've about one paragraph in an O'Reilly pamphlet, that's about it.

It's possible that they called extract() to make a point. It's also possible that somebody pulled an all-nighter and wasn't thinking too clearly at that point.

I suppose we might do well to all get a copy of the tome, now that it's been out a while, and do some discussion. Might make us all sharper, and more aware of what goes on in the publishing industry, as well.....