To get UTF-8 charset you can specify that in the DSN.
$link = new PDO("mysql:host=localhost;dbname=DB;charset=UTF8");
(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
$dsn,$username = null,$password = null,$options = nullCreates a PDO instance to represent a connection to the requested database.
dsnThe 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:
dsn contains the full DSN.
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
dsn consists of a name
name that maps to
pdo.dsn. in php.ini
defining the DSN string.
name
Зауваження:
The alias must be defined in php.ini, and not .htaccess or httpd.conf
usernameThe user name for the DSN string. This parameter is optional for some PDO drivers.
passwordThe password for the DSN string. This parameter is optional for some PDO drivers.
optionsA key=>value array of driver-specific connection options.
PDO::__construct() throws a PDOException if the attempt
to connect to the requested database fails, regardless of which PDO::ATTR_ERRMODE is currently set.
Приклад #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);
?>Приклад #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);
?>Приклад #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);
?>To get UTF-8 charset you can specify that in the DSN.
$link = new PDO("mysql:host=localhost;dbname=DB;charset=UTF8");To specify a database connection port use the following DSN string
<?php
$dsn = 'mysql:dbname=testdb;host=127.0.0.1;port=3333';
?>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.s3DBTo 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.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.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);
}
}
?>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"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);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\''));
?>// set DEFAULT_FETCH_MODE
<?php
try {
$p = new PDO("mysql:host=$db_host;port=$db_port;dbname=$db_dbname", $db_user, $db_pass,array(
PDO::ATTR_DEFAULT_FETCH_MODE =>PDO::FETCH_ASSOC,
PDO::MYSQL_ATTR_INIT_COMMAND => 'SET NAMES utf8', //after php5.3.6
));
//$p->exec('SET NAMES utf8');
} catch (PDOException $e) {
print "Error!: " . $e->getMessage() . "<br/>";
die();
}
?>Sqlite:
<?php
try{
$pdo = new PDO('sqlite:example.db');
}catch (PDOException $e){
die ('DB Error');
}
?>
If 'example.db' does not exist, no exception is thrown but the file 'example.db' is created.You will get a fatal error if you don't catch the exception threw by PDO when it fails to connect to the database server like this.
Fatal error: in xxx.php on line xx
This error neither can be handled by error handlers nor can it be erased by the @ sign, which can make your script uncontrollable.
<?php
$db = new pdo('mysql:host=127.0.0.1;port=3306;dbname=mysql;charset=utf8','user','password',array(
PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
));
?>
You should always try ... catch ...
<?php
try{
$db = new pdo('mysql:host=127.0.0.1;port=3306;dbname=mysql;charset=utf8','user','password',array(
PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
));
}catch(PDOException $pe){
echo $pe->getMessage();
}
?>Although not explicitly stated, parameters in the PDO $dsn string may be case-sensitive on some platforms or drivers.
<?php
// The dbname will not be parsed with incorrect casing:
$pdo = new PDO("mysql:host=hostname;DBName=database", "user", "password");
// The correct dbname is lowercase, as displayed in the manual:
$pdo = new PDO("mysql:host=hostname;dbname=database", "user", "password");
?>SQLite3: by default, the database file is created on opening if it does not exist (PDO::SQLITE_OPEN_CREATE).
<?php
$dsn = 'sqlite:D:\Databases\non_existing.db'; // file does not exist
try {
$dbh = new PDO($dsn);
}
catch(PDOException $e) {
print $e->getMessage();
}
?>
No Exception is thrown, instead file "non_existing.db" will be created. To avoid this, use:
<?php
$dsn = 'sqlite:D:\Databases\non_existing.db';
$options = [
PDO::SQLITE_ATTR_OPEN_FLAGS => PDO::SQLITE_OPEN_READWRITE,
];
try {
$dbh = new PDO('sqlite:D:\Databases\non_existing.db', null, null, $options);
}
catch(PDOException $e) {
print $e->getMessage();
}
?>
This will ouput:
SQLSTATE[HY000] [14] unable to open database file
If you want to open the database read-only, use PDO::SQLITE_OPEN_READONLY.