Choosing an API

PHP offers three different APIs to connect to MySQL. Below we show the APIs provided by the mysql, 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.

Example #1 Comparing the three MySQL APIs

  <?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' ]);

 // mysql
 $c  =  mysql_connect ( "example.com" ,  "user" ,  "password" );
 mysql_select_db ( "database" );
 $result  =  mysql_query ( "SELECT 'Hello, dear MySQL user!' AS _message FROM DUAL" );
 $row  =  mysql_fetch_assoc ( $result );
echo  htmlentities ( $row [ '_message' ]);
 ?>

Recommended API

It is recommended to use either the mysqli or PDO_MySQL extensions. It is not recommended to use the old mysql extension for new development, as it has been deprecated as of PHP 5.5.0 and will be removed in the future. A detailed feature comparison matrix is provided below. The overall performance of all three 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%.

Feature comparison

	ext/mysqli	PDO_MySQL	ext/mysql
PHP version introduced	5.0	5.1	2.0
Included with PHP 5.x	Yes	Yes	Yes
Development status	Active	Active	Maintenance only
Lifecycle	Active	Active	Deprecated
Recommended for new projects	Yes	Yes	No
OOP Interface	Yes	Yes	No
Procedural Interface	Yes	No	Yes
API supports non-blocking, asynchronous queries with mysqlnd	Yes	No	No
Persistent Connections	Yes	Yes	Yes
API supports Charsets	Yes	Yes	Yes
API supports server-side Prepared Statements	Yes	Yes	No
API supports client-side Prepared Statements	No	Yes	No
API supports Stored Procedures	Yes	Yes	No
API supports Multiple Statements	Yes	Most	No
API supports Transactions	Yes	Yes	No
Transactions can be controlled with SQL	Yes	Yes	Yes
Supports all MySQL 5.1+ functionality	Yes	Most	No

用户评论:

[#1] roland at mxchange dot org [2013-04-02 11:33:18]

To solve PDO limitations as described by michaeln at associations plus dot see eh, you may try to overwrite PDO methods:

<?php class MyPdo extends PDO { // What ever parameters PDO wants + prepend some own: public function query($caller, $line, $foo, $bar, $bazz) { // Do your stuff here with $caller, $line (e.g. logging for debug purposes) // Then call the extended method return parent::QUERY($foo, $bar, $bazz) or $this->myErrorHandler($caller, $line, $someSqlToLog); } } ?>

This is only a very basic example. You may otherwise choose to "wrap" the PDO class and save an instance of the "underlaying" PDO class inside the wrapper class. This is maybe a little more complex approach but allows you to have on interfaces in class signature + way better flexibility.

[#2] michaeln at associations plus dot see eh [2013-03-12 14:49:31]

Another useful consideration to keep in mind when choosing your library is how extensible it is. Chances are, in any sufficiently advanced development scenario, you're going to be extending your database access class to add a method (or multiple methods) for how to handle database errors and alert the development team of errors and whether to have the code fail immediately or fail gracefully serving the user a user-friendly failure notice.

For example, I have a class where I have added extra parameters to the query() function (and a few others), which accept the __FILE__ and __LINE__ constants to facilitate tracking issues. If this were not reasonably possible with PDO-mysql for example (not sure, never used it), it may make one option or the other much less likely to be viable for your usage case.

[#3] alvaro at demogracia dot com [2012-06-21 09:29:54]

Apart from the feature list, I suggest you try out both MySQLi and PDO and find out what API design you like most. MySQLi is more powerful and probably more complex to learn. PDO is more elegant and has the advantage that you only need to learn one PHP API if you need to work with different DBMS in the future.