PDO::commit
To specify a database connection port use the following DSN string
<?php
$dsn = 'mysql:dbname=testdb;host=127.0.0.1;port=3333';
?>
PDO::__construct
(PHP 5 >= 5.1.0, PECL pdo >= 0.1.0)
PDO::__construct — Creates a PDO instance representing a connection to a database
Description
PDO::__construct()
( string
$dsn
[, string $username
[, string $password
[, array $driver_options
]]] )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.
- driver_options
-
A key=>value array of driver-specific connection options.
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();
}
?>
add a note
User Contributed Notes
PDO::__construct - [4 notes]
subme at interia dot pl ¶
4 years ago
piotrekkr at o2 dot pl ¶
2 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.
Victor T. ¶
2 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\''));
?>
Mitsuaki Ishimoto ¶
2 years ago
You have to use the following option "MYSQL_ATTR_READ_DEFAULT_FILE" to prevent someone from attacking your system by SQL Injection.
<?php
$dsn = 'mysql:host=' . DB_HOST . ';dbname=' . DB_NAME;
$dbh = new PDO(
$dsn,
DB_USER,
DB_PASS,
array(
PDO::MYSQL_ATTR_READ_DEFAULT_FILE => '/etc/my.cnf'
)
);
$dbh->setAttribute(PDO::ATTR_EMULATE_PREPARES, false);
?>