To get UTF-8 charset you can specify that in the DSN.
$link = new PDO("mysql:host=localhost;dbname=DB;charset=UTF8");| CARVIEW |
Select Language
HTTP/2 200
server: myracloud
date: Wed, 15 Oct 2025 19:09:55 GMT
content-type: text/html; charset=utf-8
content-language: en
permissions-policy: interest-cohort=()
x-frame-options: SAMEORIGIN
link: ; rel=shorturl
last-modified: Wed, 15 Oct 2025 18:07:59 GMT
content-encoding: gzip
vary: accept-encoding
expires: Wed, 15 Oct 2025 19:09:55 GMT
cache-control: max-age=0
PHP: PDO::__construct - Manual
PDO::__construct
(PHP 5 >= 5.1.0, PHP 7, PHP 8, PECL pdo >= 0.1.0)
PDO::__construct — Creates a PDO instance representing a connection to a database
Description
public PDO::__construct(
string
?string
#[\SensitiveParameter] ?string
?array
)
string
$dsn,?string
$username = null,#[\SensitiveParameter] ?string
$password = null,?array
$options = null)
Creates a PDO instance to represent a connection to the requested database.
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
dsnparameter supports three different methods of specifying the arguments required to create a database connection:- Driver invocation
-
dsncontains the full DSN. - URI invocation
-
dsnconsists ofuri: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
-
dsnconsists of a namenamethat maps topdo.dsn.in php.ini defining the DSN string.nameNote:
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.
password-
The password for the DSN string. This parameter is optional for some PDO drivers.
options-
A key=>value array of driver-specific connection options.
Errors/Exceptions
A PDOException is thrown if the attempt
to connect to the requested database fails,
regardless of which PDO::ATTR_ERRMODE is currently set.
Examples
Example #1 Create a PDO instance via driver invocation
<?php
$dsn = 'mysql:dbname=testdb;host=127.0.0.1';
$user = 'dbuser';
$password = 'dbpass';
$dbh = new PDO($dsn, $user, $password);
?>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
$dsn = 'uri:file:///usr/local/dbconnect';
$user = '';
$password = '';
$dbh = new PDO($dsn, $user, $password);
?>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
$dsn = 'mydb';
$user = '';
$password = '';
$dbh = new PDO($dsn, $user, $password);
?>
＋add a note
User Contributed Notes 9 notes
Kiipa at live dot com ¶
11 years ago
subme at interia dot pl ¶
16 years ago
To specify a database connection port use the following DSN string
<?php
$dsn = 'mysql:dbname=testdb;host=127.0.0.1;port=3333';
?>
piotrekkr at o2 dot pl ¶
15 years ago
To connect throught unix socket you need to use
<?php
$dsn = 'mysql:dbname=testdb;unix_socket=/path/to/socket';
?>
You musn't specify host when using socket.
Aymeric S ¶
5 years ago
When trying to connect to a local database, it seems "uri:file:///" is no longer needed. Just write the PDO pilot name followed by the absolute path of the file.
Example : sqlite:C:\VirtualHosts\phpliteadmin\dbs\surveillance_logeas.s3DB
daviddlavier at gmail dot com ¶
9 years ago
I'd like to point out that in PHP 7.0 in the dsn parameter you can't use 'host=localhost' to solve this you can use 'host=127.0.0.1' instead.
theking2 at king dot ma ¶
2 years ago
A generic pattern to connect to a mariadb or mysql database using a settings file
<?php
$_SETTINGS = parse_ini_file('./settings.ini', true);
$db = new \PDO(
"mysql:hostname={$_SETTINGS['db']['host']};dbname={$_SETTINGS['db']['name']}",
$_SETTINGS['db']['user'],
$_SETTINGS['db']['pass'],
[
\PDO::ATTR_DEFAULT_FETCH_MODE => \PDO::FETCH_ASSOC,
\PDO::MYSQL_ATTR_INIT_COMMAND => "SET NAMES 'utf8mb4'"
]
);
?>
You might not need the options depicted here but I find them convenient.
Works with a settings.ini file containing for instance:
[db]
host = "localhost"
name = "dbname"
user = "dbuser"
pass = "dbpassword"
Francesco Montanari ¶
5 years ago
Most of the information in the comment here is outdated or wrong.
You do can use host=localhost to connect via socket, which is faster than TCP, so setting 127.0.0.1 is a performance loss.
To use proper utf you should use utf8mb4, for example:
$db = new PDO('mysql:host=' . DATABASE_HOST . ';dbname='. DATABASE_NAME .';charset=utf8mb4', DATABASE_USER, DATABASE_PASSWORD);
Victor T. ¶
15 years ago
If you use the UTF-8 encoding, you have to use the fourth parameter :
<?php
$db = new PDO('mysql:host=myhost;dbname=mydb', 'login', 'password', array(PDO::MYSQL_ATTR_INIT_COMMAND => 'SET NAMES \'UTF8\''));
?>
Michal Stefanak ¶
2 years ago
If you override PDO with own class and you want to implement alias from php.ini, you have to get it with `get_cfg_var` instead of `ini_get`.
<?php
class PDO extends \PDO
{
public function __construct(string $dsn, ?string $username = null, ?string $password = null, ?array $options = null)
{
//alias
if (!str_contains($dsn, ':')) {
$dsn = get_cfg_var('pdo.dsn.' . $dsn);
if (!$dsn) {
throw new PDOException('Argument #1 ($dsn) must be a valid data source name');
}
}
// your additional logic
parent::__construct($dsn, $username, $password, $options);
}
}
?>
↑ and ↓ to navigate •
Enter to select •
Esc to close
Press Enter without
selection to search using Google