[RESOLVED] Problem connecting to MySQL through PHP

Sarcastic

On my local WinXP Pro machine running IIS 5.1 and PHP 5.2.10 I have installed MySQL 5.1 and it's running ok through the MySQL Command Line. I have created a new database, new table and loaded the table with data.

Now I am trying to access that data through PHP and I am getting an error that reads...
"PHP has encountered an Access Violation at 0101AC6A "

I'm not sure what I am doing wrong.

Do I need to make changes to my php.ini file? Something else?

Any ideas?

sneakyimp

That sounds ugly. I think it means PHP is trying to access something for which it does not have permission. When does the error occur? Like what are you doing to trigger it?

Sarcastic

all I'm trying to do right now is just connect to the database using the following code...

<?php
     $con=mysql_connect("host","user","pw");
          if (!$con)
               {
               die('Could not connect: ' . mysql_error());
               }

 echo "This will first save the connection into a variable and then connect to the database.";
?>

what I've tried since my first post is since this is all on my local machine I decided to create a test database on our purchase hosting and then uploading the above script onto the server and tried running it and it worked. So I know the script is right, it just wont work from my local machine.

sneakyimp

I don't think I'm going to be much help here, but it sounds to me like there might be a MySQL-related file or resource (like a socket) that PHP cannot access due to lack of proper permissions. Do your PHP scripts that don't use any mysql run OK or do they also have problems? like try something simple:

<?php
echo 'hello world';
?>

Also, are you running your PHP from the command line or through a web server?

Sarcastic

nope, no problems with any of my php scripts. well, other than the ones with the MySQL in them now.

and I am running my PHP through a web server (IIS 5.1) that is running locally.

sneakyimp

I googled a bit and found this which tells you to look at your PHP.ini file...there is probably some kind of path specified for which your webserver doesn't have proper permissions:
http://www.faqts.com/knowledge_base/view.phtml/aid/2027

Also, on this page some guy recommends reinstalling windows, etc:
http://forums.mysql.com/read.php?11,172855

This thread has a more gloomy outlook:
http://www.vbulletin.com/forum/showthread.php?204522-HTTP-500-PHP-Access-Violation-on-IIS-w-ISAPI

Not sure what to tell beyond that it appears to be a permissions issue. The IIS user will need permission to read and/or write and/or execute anything mentioned in PHP.ini.

Sarcastic

ok... I'll have to read through those a bit more because after a quick once over I'm a bit lost/confused. I'm still very new to all this.

sneakyimp

The basic idea is that PHP is started by the web server (i think that's the case anyway) and this seems to work fine until you try and do something with mysql. There might be a temporary file folder or some resource that's supposed to be shared between MySQL and IIS/PHP which IIS cannot access. Looking in the PHP.ini for all file and path references is a good place to start. For each file/path reference, check the permissions of that file/path and make sure that IIS has permission to read/write/execute it as necessary.

Sarcastic

ok, thats sorta makes sense....

so this would be a file/path referrence correct?

;upload_tmp_dir =

does it matter that it still has the semicolon in front?
what if it doesn't have the semicolon but it's empty?

also, how do I tell if IIS has permission to that file/path?

sneakyimp

The semicolon is a comment -- that line is not evaluated because it is 'commented out.' Empty values are apparently fine. The php.ini on my office Mac dev server here is full of empty ones.

As for giving IIS permission, I'm not really sure how in Win XP. I'm a linux guy. XP supports multiple user logins on a given machine but I don't know for sure if IIS runs as a different user than your login or what. Now that I think about it, it might be running as you. You might try looking at [man]phpinfo[/man]'s output in the environment section and see what name is in the USER value.

To share a file in Win XP on my desktop here, I can right-click an object and select 'properties' and then click on the 'sharing' tab. It's kind of self-explanatory from there.

Sarcastic

right, I just wasn't sure if maybe a file/path is commented out that I might need? Or is that probably not the case? Basically as long as IIS has permission to any file/path listed in my php.ini file I am fine?

in the enviroment section of phpinfo() I see...

USERPROFILE | C:\Documents and Settings\Default User

now, thats not actually the account that I am using. The account I am using is the only account listed on this computer (when looking at the Users from the Control Panel) but for whatever reason that is what it reads. Is this normal or is this a problem? Anyway of changing that?

I dont see anything that reads USERNAME or anything like that either.

sneakyimp

I don't really have good answers to these questions. If IIS tries to access something on behalf of PHP, it's going to need the right permissions.

As for the userprofile -- that's windows-centric and I couldn't tell you how to change it or anything. Perhaps you should repost this in the install forum here?

Sorry I can't be of more assistance, I just don't know.

Sarcastic

well thank you for trying anyways. I appreciate it.

if anyone else has any ideas please let me know. Otherwise I guess I will ask in the install forum.

bradgrafelman

The error message you're getting has nothing to do with a file permissions issue. The "access violation" is dealing with accessing a memory location (one that the parent executable doesn't have access to, obviously), not a file or folder.

If you do a phpinfo(), what version of PHP are you running and what does the Client API Version say under the mysql table on that page?

EDIT: Also, how is PHP integrated with IIS? As an ISAPI module or a CGI binary?

Sarcastic

PHP Version 5.2.10

mysql -> Client API Version 5.1.38

PHP is integrated with IIS as an ISAPI module

sorry for the delay response, I was out of town for my birthday.

bradgrafelman

What version of MySQL server are you using? I'm not so sure as to what is causing this problem, but here are some possible solutions you might consider:

Use a newer library. The 'mysql_*' functions have been deprecated in favor of either [man]MySQLi[/man], the newer "improved" library, or perhaps even something like [man]PDO[/man].
Try using the same version of MySQL server as the client library PHP is using. Above, you said PHP is reporting the mysql client library version is 5.1.38. Try either installing the same version of MySQL server, OR try finding a newer libmysql.dll file and replacing the one PHP is using.
Upgrade to PHP 5.2.11. Although I didn't see any SQL-specific changes, you never know. If the above doesn't work, you could always...
... open a bug report at php.net. They'll possibly turn you away for using an older, deprecated SQL library, but hey... it's worth a shot. 🙂

Sarcastic

I have MySQL v5.1.38 installed.

I tried a mysqli_connect("host","user","password","database") script and it worked!

any ideas why mysqli_connect() would work but mysql_connect() wont?

from phpinfo() in the mysqli section the Client API library version is 5.1.38.

this may be a silly question but with me just learning MySQL, is MySQLi very similar to MySQL in the way the scripts are written?

bradgrafelman

Sarcastic wrote:
any ideas why mysqli_connect() would work but mysql_connect() wont?

It may have to do with the number and order of extensions you have loaded. To test this theory, try commenting out all "extension=" lines in your php.ini file except for the 'mysql' extension, restart your webserver, and then try using mysql_connect() again.

Sarcastic wrote:
this may be a silly question but with me just learning MySQL, is MySQLi very similar to MySQL in the way the scripts are written?

Well... yes and no. [man]MySQLi[/man] does have procedural-style functions (e.g. [man]mysqli_connect/man, [man]mysqli_query/man, etc.), but there is also an OOP method of using it as well. You'll see this double notation in the manual for the MySQLi functions/methods; one for procedural-style code, and one for OOP-style.

I'd really recommend you find a guide/book/whatever that's up-to-date and specifically talks about MySQLi (vs. MySQL) and PHP5.

tl;dr: Yes, there are similarities between the two libraries, but no, you can't just replace "mysql" with "mysqli" and expect everything to work.

Sarcastic

bradgrafelman;10936074 wrote:
It may have to do with the number and order of extensions you have loaded. To test this theory, try commenting out all "extension=" lines in your php.ini file except for the 'mysql' extension, restart your webserver, and then try using mysql_connect() again.

I will give that a shot and see what happens.

bradgrafelman;10936074 wrote:
I'd really recommend you find a guide/book/whatever that's up-to-date and specifically talks about MySQLi (vs. MySQL) and PHP5.

do you have any recommendations for a good guide or book?

sneakyimp

Start with the mysqli docs. I've noticed that new mysql functions generally require you to specify a database link. mysql just assumes the last one connected is what you want. Also [man]mysqli_connect[/man] lets you specify which database you want to use, obviating the need to select a database in a separate step.