What is PDO? Characteristics of PDO and how to install PDO

What is PDO? Characteristics of PDO and how to install PDO

What is PDO?

PDO is the abbreviation of PHP Date Object (PHP Data Object). It is released together with PHP5.1 version. Currently supported databases include Firebird, FreeTDS, Interbase, MySQL, MS SQL Server, ODBC, Oracle, Postgre SQL, SQLite and Sybase, etc., with PDO, users no longer need to use mysql_* functions, aco_* functions or mssql_* functions, nor do they need to encapsulate them into database operation classes, they only need to use The methods in the PDO interface can operate on different databases. When selecting different databases, you only need to modify the DNS (database name) of PDO.

In PHP 6, PDO is used by default to connect to the database. All non-PDO extensions will be removed in PHP 6. This extension provides the PHP built-in class PDO to access the database. Different databases use the same method name. , thereby solving the problem of inconsistent database connections.

Characteristics of PDO

(1) PDO is a "database access abstraction layer", which functions as an access interface for various databases and interacts with Compared with the mysql function library and the mssql function library, PDO makes cross-database use more friendly. Compared with ADODB and MDB2, PDO is more efficient.

(2) PDO will unify the common features of various RDBMS libraries through a lightweight, clear, and convenient function to achieve the greatest degree of abstraction and compatibility of PHP scripts.

(3) PDO learns lessons from successful and failed expansions of existing databases, and uses the latest features of PHP5 to easily interact with various databases.

(4) The PDO extension is modular, enabling you to load the driver for your own database backend while the program is running, without having to recompile or install the entire PHP program. For example: the PDO_MySQL extension will replace the PDO extension to implement the MySQL database API. There are also drivers for Oracle, PostgreSQL, ODBC and Firebird, with more in development.

POD installation

PDO is released with PHP5.1 and is included in the PHP5.1 installation file by default. Since PDO requires PHP 5 object-oriented features, so it cannot be used in versions prior to PHP 5.0.

By default, PDO is not enabled in PHP5.2, but to enable support for a certain database driver, corresponding configuration operations are required, which are configured in different operating system environments. The method is as follows:

(1) In a Linux environment, use the MySQL database. You can add the following options to the configure command:

--with-pdo-mysql=/path/to/mysql/installation

(2) In a Windows environment, enabling PDO needs to be configured in the php.ini file. To enable PDO, you must first load "extension=php_pdo.dll". If you want it to support a specific database, you must also record the corresponding database options. For example, if you want to support the MySQL database, you also need to load the "extension=php_pdo_mysql.dll" option.

Note:

After completing the loading of the database, save the php.ini file and restart the Apache server for the modification to take effect!

After reading this article, I believe everyone has a certain understanding of PDO. Below we will introduce the PDO constructor and DSN. For details, please read "Detailed explanation of using the PDO constructor to connect to the database and DSN》

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