This section holds common questions about relation between PHP and databases. Yes, PHP can access virtually any database available today.
I heard it's possible to access Microsoft SQL Server from PHP. How?
On Windows machines, you can simply use the included ODBC support and the correct ODBC driver.
On Unix machines, you can use the Sybase-CT driver to access Microsoft SQL Servers because they are (at least mostly) protocol-compatible. Sybase has made a » free version of the necessary libraries for Linux systems. For other Unix operating systems, you need to contact Sybase for the correct libraries. Also see the answer to the next question.
Can I access Microsoft Access databases?
Yes. You already have all the tools you need if you are running entirely under Windows 9x/Me, or NT/2000, where you can use ODBC and Microsoft's ODBC drivers for Microsoft Access databases.
If you are running PHP on a Unix box and want to talk to MS Access on a Windows box you will need Unix ODBC drivers. » OpenLink Software has Unix-based ODBC drivers that can do this.
Another alternative is to use an SQL server that has Windows ODBC drivers and use that to store the data, which you can then access from Microsoft Access (using ODBC) and PHP (using the built in drivers), or to use an intermediary file format that Access and PHP both understand, such as flat files or dBase databases. On this point Tim Hayes from OpenLink software writes:
Using another database as an intermediary is not a good idea, when you can use ODBC from PHP straight to your database - i.e. with OpenLink's drivers. If you do need to use an intermediary file format, OpenLink have now released Virtuoso (a virtual database engine) for NT, Linux and other Unix platforms. Please visit our » website for a free download.
One option that has proved successful is to use MySQL and its MyODBC drivers on Windows and synchronizing the databases. Steve Lawrence writes:
Tips and Tricks:
I upgraded to PHP 4, and now mysql keeps telling me "Warning: MySQL: Unable to save result set in ...". What's up?
Most likely what has happened is, PHP 4 was compiled with the --with-mysql option, without specifying the path to MySQL. This means PHP is using its built-in MySQL client library. If your system is running applications, such as PHP 3 as a concurrent Apache module, or auth-mysql, that use other versions of MySQL clients, then there is a conflict between the two differing versions of those clients.
Recompiling PHP 4, and adding the path to MySQL to the flag, '--with-mysql=/your/path/to/mysql' usually solves the problem.
PHP 5 no longer bundles MySQL client libraries, what does this mean to me? Can I still use MySQL with PHP? I try to use MySQL and get "function undefined" errors, what gives?
Yes. There will always be MySQL support in PHP of one kind or another. The only change in PHP 5 is that we are no longer bundling the client library itself. Some reasons in no particular order:
Most systems these days already have the client library installed.
Given the above, having multiple versions of the library can get messy. For example, if you link mod_auth_mysql against one version and PHP against another, and then enable both in Apache, you get a nice fat crash. Also, the bundled library didn't always play well with the installed server version. The most obvious symptom of this being disagreement over where to find the mysql.socket Unix domain socket file.
Maintenance was somewhat lax and it was falling further and further behind the released version.
Future versions of the library are under the GPL and thus we don't have an upgrade path since we cannot bundle a GPL'ed library in a BSD/Apache-style licensed project. A clean break in PHP 5 seemed like the best option.
This won't actually affect that many people. Unix users, at least the ones who know what they are doing, tend to always build PHP against their system's libmyqlclient library simply by adding the --with-mysql=/usr option when building PHP. Windows users may enable the extension php_mysql.dll inside php.ini. For more details, see the MySQL Reference for installation instructions. Also, be sure libmysql.dll is available to the systems PATH. For more details on how, read the FAQ on setting up the Windows systems PATH. Because libmysql.dll (and many other PHP related files) exist in the PHP folder, you'll want to add the PHP folder to your systems PATH.
After installing shared MySQL support, Apache dumps core as soon as libphp4.so is loaded. Can this be fixed?
If your MySQL libs are linked against pthreads this will happen. Check using ldd. If they are, grab the MySQL tarball and compile from source, or recompile from the source rpm and remove the switch in the spec file that turns on the threaded client code. Either of these suggestions will fix this. Then recompile PHP with the new MySQL libs.
Why do I get an error that looks something like this: "Warning: 0 is not a MySQL result index in <file> on line <x>" or "Warning: Supplied argument is not a valid MySQL result resource in <file> on line <x>"?
You are trying to use a result identifier that is 0. The 0 indicates that your query failed for some reason. You need to check for errors after submitting a query and before you attempt to use the returned result identifier. The proper way to do this is with code similar to the following:
<?php
$result = mysql_query("SELECT * FROM tables_priv");
if (!$result) {
echo mysql_error();
exit;
}
?>
<?php
$result = mysql_query("SELECT * FROM tables_priv")
or die("Bad query: " . mysql_error());
?>