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php-doc-en/reference/mysqlinfo/set.xml
George Peter Banyard 67d2e5fb1d
Remove mysqlnd plugin docs
2021-05-31 16:24:50 +01:00

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<?xml version="1.0" encoding="utf-8"?>
<!-- $Revision$ -->
<set xml:id="set.mysqlinfo">
<title>MySQL Drivers and Plugins</title>
<titleabbrev>MySQL</titleabbrev>
<info xml:id="mysqlinfo.info">
<abstract>
<para>
PHP offers several MySQL drivers and plugins for accessing and
handling MySQL.
</para>
<para>
The differences and functionality of the MySQL extensions are described
within the overview of this section.
</para>
</abstract>
</info>
<book xml:id="mysql">
<title>Overview of the MySQL PHP drivers</title>
<info xml:id="mysqlinfo.intro">
<title>Introduction</title>
<abstract>
<para>
There are several PHP APIs
for accessing the MySQL database. Users can choose between the
<link linkend="book.mysqli">mysqli</link> or
<link linkend="ref.pdo-mysql">PDO_MySQL</link> extensions.
</para>
<para>
This guide explains the
<link linkend="mysqlinfo.terminology">terminology</link> used to describe
each API, information about
<link linkend="mysqlinfo.api.choosing">choosing which API</link> to
use, and also information to help choose which MySQL
<link linkend="mysqlinfo.library.choosing">library to use</link> with
the API.
</para>
</abstract>
</info>
<chapter xml:id="mysqlinfo.terminology" xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink">
<title>Terminology overview</title>
<para>
This section provides an introduction to the options available to
you when developing a PHP application that needs to interact with a
MySQL database.
</para>
<para>
<emphasis role="bold">What is an API?</emphasis>
</para>
<para>
An Application Programming Interface, or API, defines the classes,
methods, functions and variables that your application will need to
call in order to carry out its desired task. In the case of PHP
applications that need to communicate with databases the necessary
APIs are usually exposed via PHP extensions.
</para>
<para>
APIs can be procedural or object-oriented. With a procedural API you
call functions to carry out tasks, with the object-oriented API you
instantiate classes and then call methods on the resulting objects.
Of the two, the latter is usually the preferred interface, as it is
more modern and leads to better organized code.
</para>
<para>
When writing PHP applications that need to connect to the MySQL
server there are several API options available. This document
discusses what is available and how to select the best solution for
your application.
</para>
<para>
<emphasis role="bold">What is a Connector?</emphasis>
</para>
<para>
In the MySQL documentation, the term <emphasis>connector</emphasis>
refers to a piece of software that allows your application to
connect to the MySQL database server. MySQL provides connectors for
a variety of languages, including PHP.
</para>
<para>
If your PHP application needs to communicate with a database server
you will need to write PHP code to perform such activities as
connecting to the database server, querying the database and other
database-related functions. Software is required to provide the API
that your PHP application will use, and also handle the
communication between your application and the database server,
possibly using other intermediate libraries where necessary. This
software is known generically as a connector, as it allows your
application to <emphasis>connect</emphasis> to a database server.
</para>
<para>
<emphasis role="bold">What is a Driver?</emphasis>
</para>
<para>
A driver is a piece of software designed to communicate with a
specific type of database server. The driver may also call a
library, such as the MySQL Client Library or the MySQL Native
Driver. These libraries implement the low-level protocol used to
communicate with the MySQL database server.
</para>
<para>
By way of an example, the <link linkend="mysqli.overview.pdo">PHP
Data Objects (PDO)</link> database abstraction layer may use one of
several database-specific drivers. One of the drivers it has
available is the PDO MYSQL driver, which allows it to interface with
the MySQL server.
</para>
<para>
Sometimes people use the terms connector and driver interchangeably,
this can be confusing. In the MySQL-related documentation the term
<quote>driver</quote> is reserved for software that provides
the database-specific part of a connector package.
</para>
<para>
<emphasis role="bold">What is an Extension?</emphasis>
</para>
<para>
In the PHP documentation, you will come across another term -
<emphasis>extension</emphasis>. The PHP code consists of a core,
with optional extensions to the core functionality. PHP's
MySQL-related extension, <literal>mysqli</literal>, is
implemented using the PHP extension framework.
</para>
<para>
An extension typically exposes an API to the PHP programmer, to
allow its facilities to be used programmatically. However, some
extensions which use the PHP extension framework do not expose an
API to the PHP programmer.
</para>
<para>
The PDO MySQL driver extension, for example, does not expose an API
to the PHP programmer, but provides an interface to the PDO layer
above it.
</para>
<para>
The terms API and extension should not be taken to mean the same
thing, as an extension may not necessarily expose an API to the
programmer.
</para>
</chapter>
<chapter xml:id="mysqlinfo.api.choosing" xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink">
<title>Choosing an API</title>
<para>
PHP offers different APIs to connect to MySQL. Below we show
the APIs provided by the mysqli and PDO extensions. Each code snippet
creates a connection to a MySQL server running on "example.com" using
the username "user" and the password "password". And a query is run to
greet the user.
</para>
<para>
<example>
<title>Comparing the MySQL APIs</title>
<programlisting role="php">
<![CDATA[
<?php
// mysqli
$mysqli = new mysqli("example.com", "user", "password", "database");
$result = $mysqli->query("SELECT 'Hello, dear MySQL user!' AS _message FROM DUAL");
$row = $result->fetch_assoc();
echo htmlentities($row['_message']);
// PDO
$pdo = new PDO('mysql:host=example.com;dbname=database', 'user', 'password');
$statement = $pdo->query("SELECT 'Hello, dear MySQL user!' AS _message FROM DUAL");
$row = $statement->fetch(PDO::FETCH_ASSOC);
echo htmlentities($row['_message']);
]]>
</programlisting>
</example>
</para>
<para>
<emphasis role="bold">Feature comparison</emphasis>
</para>
<para>
The overall performance of both extensions is considered to be about
the same. Although the performance of the extension contributes only a
fraction of the total run time of a PHP web request. Often, the impact is
as low as 0.1%.
</para>
<informaltable xml:id="mysqlinfo.api.choosing.changelog">
<tgroup cols="3">
<thead>
<row>
<entry></entry>
<entry>ext/mysqli</entry>
<entry>PDO_MySQL</entry>
</row>
</thead>
<tbody>
<row>
<entry>PHP version introduced</entry>
<entry>5.0</entry>
<entry>5.1</entry>
</row>
<row>
<entry>Included with PHP 7.x and 8.x</entry>
<entry>Yes</entry>
<entry>Yes</entry>
</row>
<row>
<entry>Development status</entry>
<entry>Active</entry>
<entry>Active</entry>
</row>
<row>
<entry>Lifecycle</entry>
<entry>Active</entry>
<entry>Active</entry>
</row>
<row>
<entry>Recommended for new projects</entry>
<entry>Yes</entry>
<entry>Yes</entry>
</row>
<row>
<entry>OOP Interface</entry>
<entry>Yes</entry>
<entry>Yes</entry>
</row>
<row>
<entry>Procedural Interface</entry>
<entry>Yes</entry>
<entry>No</entry>
</row>
<row>
<entry>API supports non-blocking, asynchronous queries with mysqlnd</entry>
<entry>Yes</entry>
<entry>No</entry>
</row>
<row>
<entry>Persistent Connections</entry>
<entry>Yes</entry>
<entry>Yes</entry>
</row>
<row>
<entry>API supports Charsets</entry>
<entry>Yes</entry>
<entry>Yes</entry>
</row>
<row>
<entry>API supports server-side Prepared Statements</entry>
<entry>Yes</entry>
<entry>Yes</entry>
</row>
<row>
<entry>API supports client-side Prepared Statements</entry>
<entry>No</entry>
<entry>Yes</entry>
</row>
<row>
<entry>API supports Stored Procedures</entry>
<entry>Yes</entry>
<entry>Yes</entry>
</row>
<row>
<entry>API supports Multiple Statements</entry>
<entry>Yes</entry>
<entry>Most</entry>
</row>
<row>
<entry>API supports Transactions</entry>
<entry>Yes</entry>
<entry>Yes</entry>
</row>
<row>
<entry>Transactions can be controlled with SQL</entry>
<entry>Yes</entry>
<entry>Yes</entry>
</row>
<row>
<entry>Supports all MySQL 5.1+ functionality</entry>
<entry>Yes</entry>
<entry>Most</entry>
</row>
</tbody>
</tgroup>
</informaltable>
</chapter>
<chapter xml:id="mysqlinfo.library.choosing" xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink">
<title>Choosing a library</title>
<para>
The mysqli and PDO_MySQL PHP extensions are lightweight wrappers on
top of a C client library. The extensions can either use the
<link linkend="book.mysqlnd">mysqlnd</link> library or the <literal>libmysqlclient</literal>
library. Choosing a library is a compile time decision.
</para>
<para>
The mysqlnd library is part of the PHP distribution. It offers
features like lazy connections and query caching, features that are not available
with libmysqlclient, so using the built-in mysqlnd library is highly recommended.
See the <link linkend="book.mysqlnd">mysqlnd documentation</link> for
additional details, and a listing of features and functionality that it offers.
</para>
<para>
<example>
<title>Configure commands for using mysqlnd or libmysqlclient</title>
<programlisting role="shell">
<![CDATA[
// Recommended, compiles with mysqlnd
$ ./configure --with-mysqli=mysqlnd --with-pdo-mysql=mysqlnd
// Alternatively recommended, compiles with mysqlnd
$ ./configure --with-mysqli --with-pdo-mysql
// Not recommended, compiles with libmysqlclient
$ ./configure --with-mysqli=/path/to/mysql_config --with-pdo-mysql=/path/to/mysql_config
]]>
</programlisting>
</example>
</para>
<para>
<emphasis role="bold">Library feature comparison</emphasis>
</para>
<para>
It is recommended to use the <link linkend="book.mysqlnd">mysqlnd</link>
library instead of the MySQL Client Server library (libmysqlclient). Both
libraries are supported and constantly being improved.
</para>
<informaltable xml:id="mysqlinfo.library.choosing.changelog">
<tgroup cols="3">
<thead>
<row>
<entry></entry>
<entry>MySQL native driver (<link linkend="book.mysqlnd">mysqlnd</link>)</entry>
<entry>MySQL client server library (<literal>libmysqlclient</literal>)</entry>
</row>
</thead>
<tbody>
<row>
<entry>Part of the PHP distribution</entry>
<entry>Yes</entry>
<entry>No</entry>
</row>
<row>
<entry>PHP version introduced</entry>
<entry>5.3.0</entry>
<entry>N/A</entry>
</row>
<row>
<entry>License</entry>
<entry>PHP License 3.01</entry>
<entry>Dual-License</entry>
</row>
<row>
<entry>Development status</entry>
<entry>Active</entry>
<entry>Active</entry>
</row>
<row>
<entry>Lifecycle</entry>
<entry>No end announced</entry>
<entry>No end announced</entry>
</row>
<row>
<entry>Compile default (for all MySQL extensions)</entry>
<entry>Yes</entry>
<entry>No</entry>
</row>
<row>
<entry>Compression protocol support</entry>
<entry>Yes</entry>
<entry>Yes</entry>
</row>
<row>
<entry>SSL support</entry>
<entry>Yes</entry>
<entry>Yes</entry>
</row>
<row>
<entry>Named pipe support</entry>
<entry>Yes</entry>
<entry>Yes</entry>
</row>
<row>
<entry>Non-blocking, asynchronous queries</entry>
<entry>Yes</entry>
<entry>No</entry>
</row>
<row>
<entry>Performance statistics</entry>
<entry>Yes</entry>
<entry>No</entry>
</row>
<row>
<entry>LOAD LOCAL INFILE respects the <link linkend="ini.open-basedir">open_basedir directive</link></entry>
<entry>Yes</entry>
<entry>No</entry>
</row>
<row>
<entry>Uses PHP's native memory management system (e.g., follows PHP memory limits)</entry>
<entry>Yes</entry>
<entry>No</entry>
</row>
<row>
<entry>Return numeric column as double (COM_QUERY)</entry>
<entry>Yes</entry>
<entry>No</entry>
</row>
<row>
<entry>Return numeric column as string (COM_QUERY)</entry>
<entry>Yes</entry>
<entry>Yes</entry>
</row>
<row>
<entry>Plugin API</entry>
<entry>Yes</entry>
<entry>Limited</entry>
</row>
<row>
<entry>Automatic reconnect</entry>
<entry>No</entry>
<entry>Optional</entry>
</row>
</tbody>
</tgroup>
</informaltable>
</chapter>
&reference.mysqlinfo.concepts;
</book>
&reference.mysqli.book;
&reference.mysql-xdevapi.book;
&reference.mysql.book;
&reference.mysqlnd.book;
</set>
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