MySQL Functions (PDO_MYSQL)

Introduzione

PDO_MYSQL is a driver that implements the PHP Data Objects (PDO) interface to enable access from PHP to MySQL databases.

PDO_MYSQL uses emulated prepares by default.

MySQL 8

When running a PHP version before 7.1.16, or PHP 7.2 before 7.2.4, set MySQL 8 Server's default password plugin to mysql_native_password or else you will see errors similar to The server requested authentication method unknown to the client [caching_sha2_password] even when caching_sha2_password is not used.

This is because MySQL 8 defaults to caching_sha2_password, a plugin that is not recognized by the older PHP (mysqlnd) releases. Instead, change it by setting default_authentication_plugin=mysql_native_password in my.cnf. The caching_sha2_password plugin is fully supported as of PHP 7.4.4. For older releases, the mysql_xdevapi extension does support it.

Nota:

The MySQL driver does not properly support PDO::PARAM_INPUT_OUTPUT via PDOStatement::bindParam(); while such parameters can be used, they are not updated (i.e. the actual output is ignored).

Installazione

The common Unix distributions include binary versions of PHP that can be installed. Although these binary versions are typically built with support for the MySQL extensions, the extension libraries themselves may need to be installed using an additional package. Check the package manager that comes with your chosen distribution for availability.

For example, on Ubuntu the php5-mysql package installs the ext/mysql, ext/mysqli, and PDO_MYSQL PHP extensions. On CentOS, the php-mysql package also installs these three PHP extensions.

Alternatively, you can compile this extension yourself. Building PHP from source allows you to specify the MySQL extensions you want to use, as well as your choice of client library for each extension.

When compiling, use --with-pdo-mysql[=DIR] to install the PDO MySQL extension, where the optional [=DIR] is the MySQL base library. Mysqlnd is the default library. For details about choosing a library, see Choosing a MySQL library.

Optionally, the --with-mysql-sock[=DIR] sets to location to the MySQL unix socket pointer for all MySQL extensions, including PDO_MYSQL. If unspecified, the default locations are searched.

Optionally, the --with-zlib-dir[=DIR] is used to set the path to the libz install prefix.

$ ./configure --with-pdo-mysql --with-mysql-sock=/var/mysql/mysql.sock

SSL support is enabled using the appropriate PDO_MySQL constants, which is equivalent to calling the » MySQL C API function mysql_ssl_set(). Also, SSL cannot be enabled with PDO::setAttribute because the connection already exists. See also the MySQL documentation about » connecting to MySQL with SSL.

Costanti predefinite

Le costanti qui sotto sono definite da questo driver, e sono disponibili solo quanto l'estensione è stata o compilata nel PHP o caricata dinamicamente a runtime. In aggiunta, queste costanti specifiche del driver dovrebbero essere usate solo se si sta usando il driver stesso. Utilizzare attributi specifici di mysql con il driver postgres può portare a risultati imprevedibili. PDO::getAttribute() può essere usata per ottenere l'attributo PDO_ATTR_DRIVER_NAME per identificare il driver, se il codice può funzionare con driver differenti.

PDO::MYSQL_ATTR_USE_BUFFERED_QUERY (bool)

By default all statements are executed in buffered mode. If this attribute is set to false on a PDO object, the MySQL driver will use the unbuffered mode.

Example #1 Setting MySQL unbuffered mode

<?php
$pdo = new PDO("mysql:host=localhost;dbname=world", 'my_user', 'my_password');
$pdo->setAttribute(PDO::MYSQL_ATTR_USE_BUFFERED_QUERY, false);

$unbufferedResult = $pdo->query("SELECT Name FROM City");
foreach ($unbufferedResult as $row) {
echo $row['Name'] . PHP_EOL;
}
?>

PDO::MYSQL_ATTR_LOCAL_INFILE (int)

Enable LOAD LOCAL INFILE.

Note, this constant can only be used in the driver_options array when constructing a new database handle.

PDO::MYSQL_ATTR_LOCAL_INFILE_DIRECTORY (string)

Allows restricting LOCAL DATA loading to files located in this designated directory. Available as of PHP 8.1.0.

Note, this constant can only be used in the driver_options array when constructing a new database handle.

PDO::MYSQL_ATTR_INIT_COMMAND (string)

Command to execute when connecting to the MySQL server. Will automatically be re-executed when reconnecting.

Note, this constant can only be used in the driver_options array when constructing a new database handle.

PDO::MYSQL_ATTR_READ_DEFAULT_FILE (int)

Read options from the named option file instead of from my.cnf. This option is not available if mysqlnd is used, because mysqlnd does not read the mysql configuration files.

PDO::MYSQL_ATTR_READ_DEFAULT_GROUP (int)

Read options from the named group from my.cnf or the file specified with MYSQL_READ_DEFAULT_FILE. This option is not available if mysqlnd is used, because mysqlnd does not read the mysql configuration files.

PDO::MYSQL_ATTR_MAX_BUFFER_SIZE (int)

Maximum buffer size. Defaults to 1 MiB. This constant is not supported when compiled against mysqlnd.

PDO::MYSQL_ATTR_DIRECT_QUERY (int)

Perform direct queries, don't use prepared statements.

PDO::MYSQL_ATTR_FOUND_ROWS (int)

Return the number of found (matched) rows, not the number of changed rows.

PDO::MYSQL_ATTR_IGNORE_SPACE (int)

Permit spaces after function names. Makes all functions names reserved words.

PDO::MYSQL_ATTR_COMPRESS (int)

Enable network communication compression.

PDO::MYSQL_ATTR_SSL_CA (int)

The file path to the SSL certificate authority.

PDO::MYSQL_ATTR_SSL_CAPATH (int)

The file path to the directory that contains the trusted SSL CA certificates, which are stored in PEM format.

PDO::MYSQL_ATTR_SSL_CERT (int)

The file path to the SSL certificate.

PDO::MYSQL_ATTR_SSL_CIPHER (int)

A list of one or more permissible ciphers to use for SSL encryption, in a format understood by OpenSSL. For example: DHE-RSA-AES256-SHA:AES128-SHA

PDO::MYSQL_ATTR_SSL_KEY (int)

The file path to the SSL key.

PDO::MYSQL_ATTR_SSL_VERIFY_SERVER_CERT (int)

Provides a way to disable verification of the server SSL certificate. This option is available only with mysqlnd.

Questo esiste dal PHP 7.0.18 and PHP 7.1.4.

PDO::MYSQL_ATTR_MULTI_STATEMENTS (int)

Disables multi query execution in both PDO::prepare() and PDO::query() when set to false.

Note, this constant can only be used in the driver_options array when constructing a new database handle.

Configurazione di Runtime

Il comportamento di queste funzioni è influenzato dalle impostazioni di php.ini.

Breve descrizione dei parametri di configurazione.

pdo_mysql.default_socket string

Sets a Unix domain socket. This value can either be set at compile time if a domain socket is found at configure. This ini setting is Unix only.

pdo_mysql.debug bool

Enables debugging for PDO_MYSQL. This setting is only available when PDO_MYSQL is compiled against mysqlnd and in PDO debug mode.