No cache version.

Caching disabled. Default setting for this page:enabled (code LNG204)
If the display is too slow, you can disable the user mode to view the cached version.

PDO::__construct

Contents

(PHP 5 >= 5.1.0, PHP 7, PECL pdo >= 0.1.0)

PDO::__construct — Creates a PDO instance representing a connection to a database

Description

public PDO::__construct ( string $dsn [, string $username [, string $passwd [, array $options ]]] )

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

PHP: PDO::__construct - Manual Home of Manuel PHP Contents Haut

Parameters

dsn

The Data Source Name, or DSN, contains the information required to connect to the database.

In general, a DSN consists of the PDO driver name, followed by a colon, followed by the PDO driver-specific connection syntax. Further information is available from the PDO driver-specific documentation.

The dsn parameter supports three different methods of specifying the arguments required to create a database connection:

Driver invocation

dsn contains the full DSN.

URI invocation

dsn consists of uri: followed by a URI that defines the location of a file containing the DSN string. The URI can specify a local file or a remote URL.

uri:file:///path/to/dsnfile

Aliasing

dsn consists of a name name that maps to pdo.dsn.name in php.ini defining the DSN string.

Note:
The alias must be defined in php.ini, and not .htaccess or httpd.conf

username

The user name for the DSN string. This parameter is optional for some PDO drivers.

passwd

The password for the DSN string. This parameter is optional for some PDO drivers.

options

A key=>value array of driver-specific connection options.

PHP: PDO::__construct - Manual Home of Manuel PHP Contents Haut

Return Values

Returns a PDO object on success.

PHP: PDO::__construct - Manual Home of Manuel PHP Contents Haut

Errors/Exceptions

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

PHP: PDO::__construct - Manual Home of Manuel PHP Contents Haut

Examples

Example #1 Create a PDO instance via driver invocation


<?php
/* Connect to a MySQL 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();
}

?>

PHP: PDO::__construct - Manual Home of Manuel PHP Contents Haut

Changelog

Version	Description
5.3.0	Classes which extends PDO and implements the __call magic method will now receive the method name in the declared casing. Previously this was always lower case.

Find a PHP function

Error Infobrol

Can not display this page of the Infobrol website

Type of error (18-01)

Unknown format specifier "&"

Please try again in a few minutes…

Return to the home page

Steph