how do you detect MySQL using PHP?

ppowell

Weird question but let me explain the background:

I am tasked with building a completely portable application that will be movable from server to server to client to client, and for now this application will only work if you are using MySQL (future implementations will allow for SQL Server and possibly even Oracle usage).

Without throwing nasty warnings and fatal errors all over the client's screen and ensuring application failure (and this is the federal government we're talking about, so, NO MORE FUNDING!), how can I detect if there is a MySQL instance out there to connect to?

I tried using ini_get() and ini_get_all() but the results are not clearly indicative of a MySQL platform existing out there.

Thanx
Phil

rachel2004

The following is very, very basic, but you'll get the idea of what I've done. The following will test TRUE on Linux if know the path to the MySQL installation. If not, you could probably do a series of other exec() functions to do a search for MySQL.

You might want to combine my example with a preceding check for what operating system is running. For example, you might do an if/else statement where IF there is a presence of a directory called WINDOWS or SYSTEM32, then the O.S. is Windows. Else it could be UNIX if those are your only two O.S. within your work area.

<?php
if (exec("/usr/local/mysql/bin/mysqladmin version -u username --password=myPassword"))
{
    echo "MySQL detected";
}
else 
{
    echo "No MySQL detected";
}
?>

ppowell

cool, thanx.. however, this application being this danged portable, will be in Unix or Solaris (I'd like to see that!) or Windows..

However, I did run across the simplest PHP method there is to find out:

if (function_exists('mysql_connect')) { // DO STUFF }

What might you think of that in regards to my needs?

Thanx
Phil

rachel2004

Well, it can certainly tell you the function is present, but my approach would also tell you that the mysqld is running. Either way would work though, as we just want to keep this simple and the snippet that you have looks simple enough if we don't need a check for the daemon running.

rachel2004

Actually, I looked at your snippet again, and it won't give you a true/false of the presence of MySQL. It will give you a true/false for the presence of a PHP function as mysql_connect is not a MySQL item, but a PHP item.

ppowell

Your response works, but I don't know how it would work in the following:

Windows environment w/o MySQL
Windows environment w/ MySQL
UNIX environment w/o MySQL

Is there somewhere I can turn to give me the desired results to find out the best possible way to tell if MySQL exists across all OS server platforms that can handle it?

Thanx
Phil

rachel2004

There might already be PHP functions that will return the operating system of the host. If so, you'd have to check the PHP manual as I don't know them off the top of my head. If not, here is a simple snippet of code:

$windows = "c:\\windows";
$winnt = "c:\\winnt";
$unix = "/";

if (is_dir($windows) || is_dir($winnt))
{
    // do check for MySQL on win32
}
else if (is_dir($unix))
{
    // do check for MySQL on UNIX
}
else 
{
    echo "Could not detect operating system.";
}

Shrike

I guess you could look for the MySQL process on *nix. I'll bet theres something similar you can do on Windows.

drew010

i suppose this could work.

if (!@mysql_connect()) {
	$reason = mysql_error();
	echo $reason;
}

i tested it on one win machine w/ no sql server installed, and the $reason was "Can't connect to MySQL server on 'localhost' (10061)"
as opposed to trying on a server with sql installed you will probably get something along the lines of "Access denied for user: 'somedefault@localhost' (Using password: NO)
that was the output on linux. the first error, 10061 usually is a socket error meaning it couldnt connect, so given mysql is running on the default port 3306 and you get the cant connect error, than it means either no server is running or its not on the default port, whereas the other error, access denied would mean it is running and gave a response to the connection. seems foolproof to me on any os.

you could even expand that to use
if (!function_exists("mysql_connect")) {
echo " sorry php isnt configured to connect to an sql server.";
} else {
//run code above
}

you can use strstr or regex on the $reason error to try to determine which error occured.

ppowell

Alright guys, I'd really love an all-out code review from the "gurus" here, your opinion on this snippet:

   // STEP 3: SET UP DATABASES/TABLES
   if (function_exists('mysql_connect')) {
    $junk = exec("mysqladmin -u $dbUser --password=$dbPwd create $dbDefaultName 2>&1");
    $junk .= exec("mysql -h $dbHost --port=$dbPort -u $dbUser --password=$dbPwd -D $dbDefaultName < $basePath/sql/ivc.sql 2>&1");
    $junk .= exec("mysql -h $dbHost --port=$dbPort -u $dbUser --password=$dbPwd -D $dbDefaultName < $basePath/sql/indexes.sql 2>&1");
    if ($junk) echo "\n$junk\n";
   }

Is this a good approach, flat out? Right now my install.php script will only be designed to handle the instance whereby you have Unix and MySQL, I honestly have no idea whatsoever to do in any of these scenarios:

Non-Unix w/ MySQL
Non-Unix w/o MySQL

I can't fathom what else to write!!

Thanx
Phil