Why does my XML data get all mixed up? - php

Question

i have a problem with getting content from a XML into a mysql database.
This is the code:
$objDOM = new DOMDocument('1.0', 'UTF-8');
$objDOM->load("something.xml"); $IAutnr = $objDOM->getElementsByTagName("Data");
Now, in a for loop:
for($i=$t;$i<=$max;$i++) {
$some= $objDOM->getElementsByTagName("some");
$something = $some->item($i)->nodeValue;
$some2 = $objDOM->getElementsByTagName("some2");
$something2 = $some2->item($i)->nodeValue;
Now put $something and $something2 into the database
}
Now, what happens is, that everything works perfectly fine until one of the Elements (some,some2...) does not exist within the tag "Data". So what he does, is taking the element from the next "Data"-tag and this mixes all my data, so I have data in my database, that actually doesnt belong there. And so I have an all mixed up database.
I allready tried for several hours to change the XML manually by putting the missing tags inside, but with thousands of data records, it is not possible.
So I need to add something into my code, that will have the effect, that if the tag doesnt exist, just leave it and dont take the tag from the next "Data"-Tag.
I actually dont even understand why he is doing that, why is he just jumping into the next "Data"-tag?
Thank you very much for your help!

Answer 1

I'm only guessing here about the content of your XML structure, but I imagine it looks something like
...
<Data>
<some>a</some>
<some2>b</some2>
</Data>
<Data>
<some>c</some>
<some2>d</some2>
</Data>
...
If this is the case, you should be looping over the collection of Data elements in $IAutnr, eg
for($i = 0, $limit = min($IAutnr->length, $max); $i < $limit; $i++) {
$data = $IAutnr->item($i);
$some = $data->getElementsByTagName('some');
$something = $some->item(0)->nodeValue;
$some2 = $data->getElementsByTagName('some2');
$something2 = $some2->item(0)->nodeValue;
// insert
}
Unless you need some of the more advanced features of the DOM library, I'd recommend using SimpleXML.

Answer 2

It does that because you're asking it to extract elements with tag name "some" and "some2" from the entire XML structure, so that's what it does -- it doesn't only look into the branch you intend it to, because you never tell it to do that. One way to fix it is to look at $some->items($i)->parentNode (and maybe to that node's parent, and so on) in order to properly identify the parent $something and $something2 belong to. Of course, there's no guarantee that $something and $something2 belong to the same parent, unless your XML is somehow guaranteed to present either none or both within the same branch. I know the explanation's a bit hairy, but that's the best way I could put it into words.