PDO->__construct()

Description

Creates a PDO instance to represent a connection to the requested database.

Parameters

Return Values

Returns a PDO object on success.

Errors/Exceptions

PDO->__construct() throws a PDOException if the attempt to connect to the requested database fails.

Examples

Example 1. Create a PDO instance via driver invocation <?php /* Connect to an ODBC database using driver invocation */ $dsn = 'mysql:dbname=testdb;host=127.0.0.1'; $user = 'dbuser'; $password = 'dbpass'; try {     $dbh = new PDO($dsn, $user, $password); } catch (PDOException $e) {     echo 'Connection failed: ' . $e->getMessage(); } ?>

Example 2. Create a PDO instance via URI invocation The following example assumes that the file /usr/local/dbconnect exists with file permissions that enable PHP to read the file. The file contains the PDO DSN to connect to a DB2 database through the PDO_ODBC driver: odbc:DSN=SAMPLE;UID=john;PWD=mypass The PHP script can then create a database connection by simply passing the uri: parameter and pointing to the file URI: <?php /* Connect to an ODBC database using driver invocation */ $dsn = 'uri:file:///usr/local/dbconnect'; $user = ''; $password = ''; try {     $dbh = new PDO($dsn, $user, $password); } catch (PDOException $e) {     echo 'Connection failed: ' . $e->getMessage(); } ?>

Example 3. Create a PDO instance using an alias The following example assumes that php.ini contains the following entry to enable a connection to a MySQL database using only the alias mydb: [PDO] pdo.dsn.mydb="mysql:dbname=testdb;host=localhost" <?php /* Connect to an ODBC database using an alias */ $dsn = 'mydb'; $user = ''; $password = ''; try {     $dbh = new PDO($dsn, $user, $password); } catch (PDOException $e) {     echo 'Connection failed: ' . $e->getMessage(); } ?>