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LXXX. MySQL Functions
In order to have these functions available, you must compile PHP with
MySQL support.
For compiling, simply use the
--with-mysql[=DIR]
configuration option where the optional [DIR] points to
the MySQL installation directory.
This MySQL extension doesn't support full functionality of MySQL versions greater than
4.1.0. For that, use MySQLi.
If you would like to install the mysql extension along with the mysqli extension
you have to use the same client library to avoid any conflicts.
The option --with-mysql is
enabled by default. This default behavior may be disabled with the
--without-mysql configure option.
If MySQL is enabled without specifying the path to the
MySQL install DIR, PHP will use the bundled MySQL client libraries.
Users who run other applications that use MySQL (for example,
auth-mysql) should not use the bundled library, but rather specify the
path to MySQL's install directory, like so:
--with-mysql=/path/to/mysql.
This will force PHP to use the client libraries installed by MySQL, thus
avoiding any conflicts.
MySQL is not enabled by default, nor is the MySQL library
bundled with PHP. Read this
FAQ for details on why. Use the
--with-mysql[=DIR] configure option
to include MySQL support.
The PHP MySQL extension is compiled into PHP.
MySQL is no longer enabled by default, so the
php_mysql.dll DLL must be enabled inside of
php.ini. Also, PHP needs access to the MySQL client library. A file
named libmysql.dll is included in the Windows PHP
distribution and in order for PHP to talk to MySQL this file needs to be
available to the Windows systems PATH. See the FAQ
titled "How do I add my PHP
directory to the PATH on Windows" for information on how to do
this. Although copying libmysql.dll to the Windows
system directory also works (because the system directory is by default in
the systems PATH), it's not recommended.
As with enabling any PHP extension (such as
php_mysql.dll), the PHP directive
extension_dir should be set to
the directory where the PHP extensions are located. See also the
Manual Windows Installation
Instructions. An example extension_dir value for PHP 5 is
c:\php\ext
Note:
If when starting the web server an error similar to the following occurs:
"Unable to load dynamic library './php_mysql.dll'",
this is because php_mysql.dll and/or
libmysql.dll cannot be found by the system.
| Warning |
Crashes and startup problems of PHP may be encountered
when loading this extension in conjunction with the recode extension.
See the recode extension for more
information.
|
Note:
If you need charsets other than latin (default), you
have to install external (not bundled) libmysql with compiled charset
support.
The behaviour of these functions is affected by settings in php.ini.
Table 1. MySQL Configuration Options | Name | Default | Changeable | Changelog |
|---|
| mysql.allow_persistent | "1" | PHP_INI_SYSTEM | | | mysql.max_persistent | "-1" | PHP_INI_SYSTEM | | | mysql.max_links | "-1" | PHP_INI_SYSTEM | | | mysql.trace_mode | "0" | PHP_INI_ALL | Available since PHP 4.3.0. | | mysql.default_port | NULL | PHP_INI_ALL | | | mysql.default_socket | NULL | PHP_INI_ALL | Available since PHP 4.0.1. | | mysql.default_host | NULL | PHP_INI_ALL | | | mysql.default_user | NULL | PHP_INI_ALL | | | mysql.default_password | NULL | PHP_INI_ALL | | | mysql.connect_timeout | "60" | PHP_INI_ALL | PHP_INI_SYSTEM in PHP <= 4.3.2. Available since PHP 4.3.0. |
For further details and definitions of the
PHP_INI_* constants, see the Appendix H.
Here's a short explanation of
the configuration directives.
- mysql.allow_persistent
boolean
Whether to allow
persistent connections
to MySQL.
- mysql.max_persistent
integer
The maximum number of persistent MySQL connections per
process.
- mysql.max_links
integer
The maximum number of MySQL connections per process, including
persistent connections.
- mysql.trace_mode
boolean
Trace mode. When mysql.trace_mode is enabled, warnings
for table/index scans, non free result sets, and SQL-Errors will be
displayed. (Introduced in PHP 4.3.0)
- mysql.default_port
string
The default TCP port number to use when connecting to
the database server if no other port is specified. If
no default is specified, the port will be obtained
from the MYSQL_TCP_PORT environment
variable, the mysql-tcp entry in
/etc/services or the compile-time
MYSQL_PORT constant, in that order. Win32
will only use the MYSQL_PORT constant.
- mysql.default_socket
string
The default socket name to use when connecting to a local
database server if no other socket name is specified.
- mysql.default_host
string
The default server host to use when connecting to the database
server if no other host is specified. Doesn't apply in
safe mode.
- mysql.default_user
string
The default user name to use when connecting to the database
server if no other name is specified. Doesn't apply in
safe mode.
- mysql.default_password
string
The default password to use when connecting to the database
server if no other password is specified. Doesn't apply in
safe mode.
- mysql.connect_timeout
integer
Connect timeout in seconds. On Linux this timeout is also used for
waiting for the first answer from the server.
There are two resource types used in the MySQL module. The first one
is the link identifier for a database connection, the second a resource
which holds the result of a query.
The constants below are defined by this extension, and
will only be available when the extension has either
been compiled into PHP or dynamically loaded at runtime.
Since PHP 4.3.0 it is possible to specify additional client flags for the
mysql_connect() and mysql_pconnect()
functions. The following constants are defined:
Table 2. MySQL client constants | Constant | Description |
|---|
| MYSQL_CLIENT_COMPRESS | Use compression protocol | | MYSQL_CLIENT_IGNORE_SPACE | Allow space after function names | | MYSQL_CLIENT_INTERACTIVE | Allow interactive_timeout seconds (instead of wait_timeout) of
inactivity before closing the connection. | | MYSQL_CLIENT_SSL | Use SSL encryption. This flag is only available with version 4.x
of the MySQL client library or newer. Version 3.23.x is bundled both
with PHP 4 and Windows binaries of PHP 5.
|
The function mysql_fetch_array() uses a constant for
the different types of result arrays. The following constants are
defined:
Table 3. MySQL fetch constants | Constant | Description |
|---|
| MYSQL_ASSOC |
Columns are returned into the array having the fieldname as the array
index.
| | MYSQL_BOTH |
Columns are returned into the array having both a numerical index
and the fieldname as the array index.
| | MYSQL_NUM |
Columns are returned into the array having a numerical index to the
fields. This index starts with 0, the first field in the result.
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This simple example shows how to connect, execute a query, print
resulting rows and disconnect from a MySQL database.
Example 1. MySQL extension overview example |
<?php
$link = mysql_connect('mysql_host', 'mysql_user', 'mysql_password')
or die('Could not connect: ' . mysql_error());
echo 'Connected successfully';
mysql_select_db('my_database') or die('Could not select database');
$query = 'SELECT * FROM my_table';
$result = mysql_query($query) or die('Query failed: ' . mysql_error());
echo "<table>\n";
while ($line = mysql_fetch_array($result, MYSQL_ASSOC)) {
echo "\t<tr>\n";
foreach ($line as $col_value) {
echo "\t\t<td>$col_value</td>\n";
}
echo "\t</tr>\n";
}
echo "</table>\n";
mysql_free_result($result);
mysql_close($link);
?>
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User Contributed Notes
MySQL Functions
medic at setiherbipolis dot de
15-May-2005 11:42
Client does not support authentication protocol requested by server; consider upgrading MySQL client
means that you're using an old version of MySQL Client ( possibly not mysqli)
Authentication protocol for MySQL has changed with version 4.1.
To get a hint at which mysql-client version you're using try phpinfo();
05-May-2005 03:24
I install php 5 and mysql 4.1. when I try to connect to mysql, I get this:
Client does not support authentication protocol requested by server; consider upgrading MySQL client
any help is appreciated.
04-May-2005 09:12
1) Windows users will need to enable php_mysql.dll inside of php.ini
2) make libmysql.dll available to the PATH
3) change this in your php.ini file:
extension_dir = "./" to something like "c:\php\ext"
jonathan at belial dot co dot uk
14-Apr-2005 03:36
I spent the last age and a day trying to get mysql 4.1.1. to tie into php 5 with no avail... be sure to set:
PHPIniDir "C:/php"
in your httpd.conf file. If you do not then phpinfo() will report that your extension directory is 2c:/php5" and thereby ignore any extensions you attempt to include in your php.ini.
Good Luck.
06-Mar-2005 02:01
If you are installing PHP5 on Windows 2003 server (AKA Win 2k3) and need MySQL to work using the either the php_mysql.dll or php_mysqli.dll or both of them at the same time, and MySQl isn't showing up in phpinfo, then your php.ini is probably not loading. In the direction in the PHP 5 zip file, they will tell you to add your PHP install directory to your windows path. This should tell php where to load its php.ini from but it doesn't. If you want to get this to work, you don't have to copy any DLL's anywhere like everyone suggests. All you have to do is add the folling regsitry key to windows:
[HKEY_LOCAL_MACHINE\SOFTWARE\PHP]
"IniFilePath"="C:\\PHP"
simply copy the above 2 lines of code into a text file and save the file as php_ini_path.reg
After you save the file it will look like a registry file. Simply double click on it.
It will make it so PHP will look for your php.ini in C:\PHP. I would assume you can edit this if you install php into a different location, but I haven't tried that.
After running the reg file, make sure your php.ini is in your PHP dir and make sure all the appropriate things are set. This should get you up and running. Make sure you also follow all the steps on how to make it work in IIS. This is just an addition to the direction.
Protik Mukherjee
03-Mar-2005 12:34
Fedora mysql problems!!
In Fedora 3 the php mysql module does not come with the default installation. To install it use $>yum install php_mysql
If u dont do this you will get errors with mysql functions like mysql_connect()
Hope this helps!
j at jonathany.com
01-Feb-2005 03:09
Users attempting to install MySQL under PHP5 on Windows may have trouble if they use the MSI installer of PHP, which does not include the DLL php_mysql.dll .
In order to succesfully install MySQL on PHP5, download the ZIP version of PHP, which includes the php_mysql.dll.
tumaine no at spam verizon net
23-Dec-2004 11:21
I had a hard time with upgrading to php version 5.2.0 in Windows XP Pro since mySQL queries all of a sudden stopped working and led to blank pages on my site. I spent a good half day searching google trying to figure out this problem, and didn't quite know how compiling PHP would help me. It is not necessary. Set up PHP manually with the ZIP folder download.
This is a good link to read and wish I found it earlier:
http://www.zend.com/manual/install.windows.extensions.php
If you are getting an error popup about not being able to load some mysql.dll when starting apache, you need to change this in your php.ini file:
extension_dir = "./" to something like "c:\php\ext"
Also what I was doing wrong was that I forgot to uncomment the following line in my php.ini file:
extension=php_mysql.dll
Restart apache, and everything should work.
Thought that I could save someone time and frustration when upgrading, since versions 5+ do not include mySQL support by default as earlier versions apparently do.
jon at mysql dot com
11-Dec-2004 05:32
Re Pat's note: You can add the --old-passwords option in the [mysqld] section of your MySQL my.cnf or my.ini configuration file. This option will force the MySQL server to use the old-style password hashing for all connections. This is not really recommended, as it's less secure, but will allow you to use existing accounts without resetting the passwords.
Of course, as already mentioned, you can use the MySQL OLD_PASSWORD() function instead to handle this issue on an account-by-account basis.
The optimal solution when migrating to MySQL 4.1+ from a previous version is to upgrade to PHP 5 (if you're not using it already) and rewrite any code accessing MySQL using the mysqli extension, which is more secure and provides a much better API.
For more information, see the MySQL Manual: http://dev.mysql.com/doc/mysql/en/Application_password_use.html
lkujala at uniserve dot com
18-Nov-2004 04:43
PROBLEM:
Error Message: the specified module could not be found.
When trying to load a php_mysql.dll / php_mysqli.dll / php_mssql.dll extension on a Windows platform.
CAUSE:
The standard windows installer package is rather incomplete; it does not include any of the DLL's needed for the optional extensions. In order to use any extension you need to install the FULL zip distribution (unless you like fooling around with dll hell), not just the php_*.dll extensions. You might as well include ALL of the DLL's since the dependencies as documented are wrong (i.e. you need more than libmysql.dll for the php_mysql.dll to load).
I did find the standard windows installer useful for the inital setup though.
22-Oct-2004 10:04
Having trouble loading extensions under windows? Seems as though php.ini is not being read at all?
Maybe the php5 installer has written a PHPIniDir directive in your httpd.conf telling php to look for php.ini in c:\php\
nleippe at integr8ted dot com
12-Oct-2004 06:22
trace_mode breaks SQL_CALC_FOUND_ROWS.
This is because it emits an EXPLAIN <query> before sending the <query> by itself, thus the subsequent SELECT FOUND_ROWS() is no longer the next consecutive query, and the result is zero.
This was true for me for at least MySQL 4.0.21 and 4.1.5gamma.
(PHP 4.3.9)
Melvin Nava: e-4(at)venezolano.web.ve
13-Sep-2004 03:02
To count page hits, just put next code in a text file and include it in every one of your pages. It will log even different querystrings as different pages. (a MySQL database and table is needed first)
This can be a pretty good example of what you can do with PHP and MySQL. I made this script to log and show all hits in: http://www.venezolano.web.ve/
<?php
function page_count($page) {
$c_link = mysql_connect('localhost', 'username', 'password')
or die('counter CONNECT error: '.mysql_errno().', '.mysql_error());
mysql_select_db('database_name');
$c_query = "SELECT * FROM stats_pagecounter
WHERE (page_name = '$page')";
$c_result = mysql_query($c_query, $c_link)
or die('counter SELECT error: '.mysql_errno().', '.mysql_error());
if (mysql_num_rows($c_result)) {
$row=mysql_fetch_array($c_result,MYSQL_ASSOC);
$pcounter = $row['page_hits']+1;
$c_update = "UPDATE stats_pagecounter
SET page_hits = '$pcounter' WHERE page_name = '$page'";
$c_hit = mysql_query($c_update, $c_link)
or die('counter UPDATE error: '.mysql_errno().', '.mysql_error());
} else {
$c_insert = "INSERT INTO stats_pagecounter
VALUES ( '0', '$page', '1')";
$c_page = mysql_query($c_insert, $c_link)
or die('counter INSERT error: '.mysql_errno().', '.mysql_error());
$pcounter = 1;
}
mysql_free_result($c_result);
mysql_close($c_link);
return $pcounter;
}
$phpself_url = $_SERVER['SERVER_NAME'].
$_SERVER['PHP_SELF'].'?'.
$_SERVER['QUERY_STRING'];
$page_hits = page_count($phpself_url);
echo $page_hits;
?>
aidan at php dot net
15-Aug-2004 08:59
irn-bru at gmx dot de
27-May-2004 08:27
Note, that the sql.safe_mode configuration setting does effect all mysql_* functions. This has nothing to to with the php safe mode, check the [SQL] section in php.ini.
I found out, that if you set sql.safe_mode = On, mysql_connect will ignore provided username and passwort and makes use of the script owner instead (checked on debian).
Brian
Pat
22-Jan-2004 06:02
[Editor Note:
The password hashing was updated in MySQL 4.1, you must use the MySQLi extension with MySQL 4.1+ (or use the following method to allow
pre 4.1 clients to connect).]
MySQL 5.0 has a new password system, and PHP cannot connect to it because it cannot send a correct password. You must use the MySQL command OLD_PASSWORD() when adding a user to the database, or PHP cannot connect as of the library that comes with PHP 5.0Beta3
gyohng at netscape dot net
20-Jun-2003 01:16
soren at byu dot edu
14-Mar-2003 04:23
Let's say that you want to generate a MySQL password hash from a plain text password. Normally, you would just submit the MySQL query "SELECT PASSWORD('password')", but if for some reason you can't access to MySQL database directly, then you can use the following function (translated right out of the MySQL source code):
<?php
function mysql_password($passStr) {
$nr=0x50305735;
$nr2=0x12345671;
$add=7;
$charArr = preg_split("//", $passStr);
foreach ($charArr as $char) {
if (($char == '') || ($char == ' ') || ($char == '\t')) continue;
$charVal = ord($char);
$nr ^= ((($nr & 63) + $add) * $charVal) + ($nr << 8);
$nr2 += ($nr2 << 8) ^ $nr;
$add += $charVal;
}
return sprintf("%08x%08x", ($nr & 0x7fffffff), ($nr2 & 0x7fffffff));
}
?>
example:
<? print mysql_password("hello"); ?>
outputs:
70de51425df9d787
Which is the same result you get if you do "SELECT PASSWORD('hello')" directly in MySQL. Hopefully you'll never be in a situation where you have to use this, but if you need it (like I did), it's here.
past at sbox dot tugraz dot at
21-Feb-2003 05:17
As MySQL docs say, RAND() is not very usefull for generation of randomized result orders.
But this worked for me on Linux, however:
Somewhere before:
mt_srand((double)microtime()*1000000);
"SELECT *, " RAND(".mt_rand(0,86622340).")*10000%100 AS randomvalue ORDER BY randomvalue"
The upper value for mt_rand() has to be Quite Big to see any effect on MySQL's RAND(). The exact number shouldn't be significant. Note the multiplication and modulo; MySQL seems to count steadily upwards when generating random numbers, so we take some numbers from between.
mijnpc at xs4all dot nl
20-Nov-2002 05:33
If you have a Windows machine running a webserver with PHP you don't need to install MySQL server to locally test scripts, if you are granted to establish a Secure Telnet connection (port 22) to the remote webserver.
To do this you need a Secure Telnet client, which supports port-forwarding.
Before you establish a connection, define the port-forward.
Forward local port 3306 to [name or ip of remote server]:3306
Make sure that local ports accept connections from other hosts
Save this session
Connect to remote server with username and password
Minimize the shell and that's it...
You can use the same username (and password) as if you were working on the remote server !
E.g. : $link = mysql_connect("localhost", "root", "") or die("no way jose");
You may get a shell-timeout after xx minutes depending on your remote server, just reconnect or press enter in the shell once in a while...
An example of a superb freeware Secure Telnet client is Putty : Putty : http://www.chiark.greenend.org.uk/~sgtatham/putty/
This 'discovery' really has saved me a lot of time because I don't have to upload the scripts to the remote server time and time again, pressing [save] is enough, heh (-:
16-Jun-2002 03:38
Regarding transactions, you must use a recent MySQL version which supports InnoDB tables. you should read the mysql manual (the part about Innodb tables, section 7.5) and configure your server to use them.
Some reading about how it works:
http://php.weblogs.com/discuss/msgReader$1446?mode=topic
(Click where it says Part2, I can't put the direct URL here because it is too long)
Then in PHP you use commands like:
mysql_query("BEGIN");
mysql_query("COMMIT");
mysql_query("ROLLBACK");
You must make sure that you convert your existing tables to innodb or create new ones: CREATE TABLE (...) type=innodb;
jeyoung at priscimon dot com
25-Apr-2002 12:23
[Ed. Note:
This may be due to the fact that subsequent calls to mysql_connect with the same parameters return the same resource id for the connection, so in reality it is using the same connection. In order to force a new link, you must specify the new_link parameter in mysql_connect.]
MySQL transactions
MySQL supports transactions on tables that are of type InnoDB. I have noticed a behaviour which is puzzling me when using transactions.
If I establish two connections within the same PHP page, start a transaction in the first connection and execute an INSERT query in the second one, and rollback the transaction in the first connection, the INSERT query in the second connection is also rolled-back.
I am assuming that a MySQL transaction is not bound by the connection within which it is set up, but rather by the PHP process that sets it up.
This is a very useful "mis-feature" (bug?) because it allows you to create something like this:
class Transaction {
var $dbh;
function Transaction($host, $username, $password) {
$this->dbh = mysql_connect($host, $username, $password);
}
function _Transaction() {
mysql_disconnect($this->dbh);
}
function begin() {
mysql_query("BEGIN", $this->dbh);
}
function rollback() {
mysql_query("ROLLBACK", $this->dbh);
}
function commit() {
mysql_query("COMMIT", $this->dbh);
}
}
which you could use to wrap around transactional statements like this:
$tx =& new Transaction("localhost", "username", "password");
$tx->begin();
$dbh = mysql_connect("localhost", "username", "password");
$result = mysql_query("INSERT ...");
if (!$result) {
$tx->rollback();
} else {
$tx->commit();
}
mysql_disconnect($dbh);
unset($tx);
The benefit of such a Transaction class is that it is generic and can wrap around any of your MySQL statements.
nospam at nospam dot nos
19-Nov-2001 12:17
ever wanted to know the date a table was last updated? use this:
$info = mysql_fetch_array(mysql_query("show table status from databasename like 'tablename'"));
echo $info["Update_time"];
skelley at diff dot nl
25-Sep-2001 05:11
Hi, here's a nice little trick to select records in random order from a table in a MySQL database prior to version 3.23
SELECT *, (ItemID/ItemID)*RAND() AS MyRandom FROM Items ORDER BY MyRandom
[Editors note: And just "SELECT * FROM foo ORDER BY RAND()" after 3.23]
mbabcock-php at fibrespeed dot net
28-Jul-2001 10:41
Since there aren't functions to start and end/rollback transactions, you'll have to use mysql_query("BEGIN"), mysql_query("COMMIT") and mysql_query("ROLLBACK"). These will only work properly on tables that support transactions. You may also wish to roll your own mysql_begin (etc) functions that run the above queries for you.
philip at cornado dot com
23-Jul-2001 03:24
mw-php at ender dot com
22-Jun-2001 12:11
The mysql_fetch_[row|object|array] functions return data as type string. Owing to the very flexible nature of php variables, this is normally not relevent, but if you happen to retrieve two integers from a database, then try to compare with bitwise operators, you'll run into trouble, because (19 & 2) == 2, but ("19" & "2") == 0. To remedy this, if you use variables from a database with bitwise operators, use the settype() function to explicitly cast your variables as integers before comparing.
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