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PDO::__construct

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PDO::__construct

(no version information, might be only in CVS)PDO::__construct --

Creates a PDO instance representing a connection to a database

Описание

PDO PDO::__construct (string dsn [, string username [, string password [, array driver_options]]])

Внимание

-Эта функция является ЭКСПЕРИМЕНТАЛЬНОЙ.

Поведение этой функции, ее имя и относящаяся к ней документация

могут измениться в последующих версиях PHP без уведомления.

Используйте эту функцию на свой страх и риск.

- Creates a PDO instance to represent a connection to the requested

database.

Список параметров

-

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. Examples of each

driver are given below:

-

PDO_DBLIB

- The DSN prefix is either sybase:

or mssql: depending on which libraries

it was linked against during compilation.

sybase:host=localhost; dbname=testdb

mssql:host=localhost; dbname=testdb

PDO_FIREBIRD

firebird:User=john;Password=mypass;Database=DATABASE.GDE;DataSource=localhost;Port=3050

PDO_MYSQL

mysql:host=localhost;dbname=testdb

PDO_OCI

To connect via tnsnames.ora, use:

oci:mydb

If using instantclient, use:

oci:dbname=//localhost:1521/testdb

PDO_ODBC

odbc:DSN=SAMPLE;UID=john;PWD=mypass

DSN=SAMPLE refers to the SAMPLE data source configured in the ODBC driver manager.

PDO_PGSQL

pgsql:host=localhost port=5432 dbname=testdb user=john password=mypass

- Note, by passing user and password

in the DSN, the username

and password parameters become optional.

If specified, they are glued to the end of the connection string.

PDO_SQLITE

sqlite:/path/to/database

To create a database in memory, use:

sqlite::memory:

sqlite (version 2)

sqlite2:/path/to/database

To create a database in memory, use:

sqlite2::memory:

Замечание:

The SQLite 2 PDO driver provides access to old SQLite 2

databases that you may have created with earlier versions

of PHP. It is recommended that you migrate to SQLite 3 (the

PDO_SQLITE driver), as it has superior features and performance.

- 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.

Замечание:

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.

Возвращаемые значения

- Returns a PDO object on success.

Исключения

- PDO::construct() throws a PDOException if the attempt

to connect to the requested database fails.

Примеры

-

Пример 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();

}

?>

Пример 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();

}

?>

Пример 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();

}

?>

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