If you're running a PHP 5.1 release, PDO and PDO_SQLITE is included in the distribution; it will be automatically enabled when you run configure. It is recommended that you build PDO as a shared extension, as this will allow you to take advantage of updates that are made available via PECL. The recommended configure line for building PHP with PDO support should enable zlib support (for the pecl installer) as well. You may also need to enable the PDO driver for your database of choice; consult the documentation for database-specific PDO drivers to find out more about that, but note that if you build PDO as a shared extension, you must build the PDO drivers as shared extensions. SQLite extension depends on PDO so if PDO is built as a shared extension, SQLite needs to be built the same way.

./configure --with-zlib --enable-pdo=shared --with-pdo-sqlite=shared --with-sqlite=shared

After installing PDO as a shared module, you must edit your php.ini file so that the PDO extension will be loaded automatically when PHP runs. You will also need to enable any database specific drivers there too; make sure that they are listed after the pdo.so line, as PDO must be initialized before the database-specific extensions can be loaded. If you built PDO and the database-specific extensions statically, you can skip this step.

extension=pdo.so

Having PDO as a shared module will allow you to run pecl upgrade pdo as new versions of PDO are published, without forcing you to rebuild the whole of PHP. Note that if you do this, you also need to upgrade your database specific PDO drivers at the same time.

PDO is available as a PECL extension from » http://pecl.php.net/package/pdo. Installation can be performed via the pecl tool; this is enabled by default when you configure PHP. You should ensure that PHP was configured --with-zlib in order for pecl to be able to handle the compressed package files.

Run the following command to download, build, and install the latest stable version of PDO:

pecl install pdo

The pecl command automatically installs the PDO module into your PHP extensions directory. To enable the PDO extension on Linux or Unix operating systems, you must add the following line to php.ini:

extension=pdo.so

For more information about building PECL packages, consult the PECL installation section of the manual.

PDO and all the major drivers ship with PHP as shared extensions, and simply need to be activated by editing the php.ini file:

extension=php_pdo.dll

Next, choose the other database-specific DLL files and either use dl() to load them at runtime, or enable them in php.ini below php_pdo.dll. For example:

extension=php_pdo.dll
extension=php_pdo_firebird.dll
extension=php_pdo_informix.dll
extension=php_pdo_mssql.dll
extension=php_pdo_mysql.dll
extension=php_pdo_oci.dll
extension=php_pdo_oci8.dll
extension=php_pdo_odbc.dll
extension=php_pdo_pgsql.dll
extension=php_pdo_sqlite.dll  

These DLLs should exist in the system's extension_dir. Note that PDO_INFORMIX is only available as a PECL extension.