Introduction to Connections

DSN, the Data Source Name

In order to connect to a database through Doctrine, you have to create a valid DSN (Data Source Name).

Doctrine supports both PEAR DB/MDB2 like data source names as well as PDO style data source names. The following section deals with PEAR like data source names. If you need more info about the PDO-style data source names see the documentation on PDO.

Main Parts

The DSN consists in the following parts:

DSN part Description
phptype Database backend used in PHP (i.e. mysql, pgsql etc.)
dbsyntax Database used with regards to SQL syntax etc
protocol Communication protocol to use ( i.e. tcp, unix etc.)
hostspec Host specification (hostname[:port]) ||
database Database to use on the DBMS server
username User name for login
password Password for login
proto_opts Maybe used with protocol
option Additional connection options in URI query string format. Options are separated by ampersand (&). The following section shows a non-complete list of options.

Options

Name Description
charset Some backends support setting the client charset.
new_link Some RDBMS do not create new connections when connecting to the same host multiple times. This option will attempt to force a new connection.

Providing the DSN

The DSN can either be provided as an associative array or as a string. The string format of the supplied DSN is in its fullest form:

phptype(dbsyntax)://username:password@protocol+hostspec/database?option=value

Most variations are allowed:

phptype://username:password@protocol+hostspec:110//usr/db_file.db
phptype://username:password@hostspec/database
phptype://username:password@hostspec
phptype://username@hostspec
phptype://hostspec/database phptype://hostspec phptype:///database
phptype:///database?option=value&anotheroption=anothervalue
phptype(dbsyntax) phptype

The currently supported PDO database drivers are:

Driver name Supported databases
fbsql FrontBase
ibase InterBase / Firebird (requires PHP 5)
mssql Microsoft SQL Server (NOT for Sybase. Compile PHP –with-mssql)
mysql MySQL
mysqli MySQL (supports new authentication protocol) (requires PHP 5)
oci Oracle 7/8/9/10
pgsql PostgreSQL
querysim QuerySim
sqlite SQLite 2

A second DSN format supported is

phptype(syntax)://user:pass@protocol(proto_opts)/database

If your database, option values, username or password contain characters used to delineate DSN parts, you can escape them via URI hex encodings:

Character Hex Code
: %3a
/ %2f
@ %40
+ %2b
( %28
) %29
? %3f
= %3d
& %26

Please note, that some features may be not supported by all database drivers.

Examples

  1. Connect to database through a socket

    mysql://user@unix(/path/to/socket)/pear
    
  2. Connect to database on a non standard port

    pgsql://user:pass@tcp(localhost:5555)/pear
    

    Note

    If you use, the IP address 127.0.0.1, the port parameter is ignored (default: 3306).

  3. Connect to SQLite on a Unix machine using options

    sqlite:////full/unix/path/to/file.db?mode=0666
    
  4. Connect to SQLite on a Windows machine using options

    sqlite:///c:/full/windows/path/to/file.db?mode=0666
    
  5. Connect to MySQLi using SSL

    mysqli://user:pass@localhost/pear?key=client-key.pem&cert=client-cert.pem
    

Opening New Connections

Opening a new database connection in Doctrine is very easy. If you wish to use PDO you can just initialize a new :php:class:`PDO` object.

Remember our bootstrap.php file we created in the Getting Started chapter? Under the code where we registered the Doctrine autoloader we are going to instantiate our new connection:

// bootstrap.php
$dsn = 'mysql:dbname=testdb;host=127.0.0.1';
$user = 'dbuser';
$password = 'dbpass';

$dbh = new PDO($dsn, $user, $password);
$conn = Doctrine_Manager::connection($dbh);

Tip

Directly passing a PDO instance to Doctrine_Manager::connection will not allow Doctrine to be aware of the username and password for the connection, since their is no way to retrieve it from an existing PDO instance. The username and password is required in order for Doctrine to be able to create and drop databases. To get around this you can manually set the username and password option directly on the $conn object.

// bootstrap.php
$conn->setOption('username', $user);
$conn->setOption('password', $password);

Lazy Database Connecting

Lazy-connecting to database can save a lot of resources. There might be many times where you don’t need an actual database connection, hence its always recommended to use lazy-connecting (that means Doctrine will only connect to database when needed).

This feature can be very useful when using for example page caching, hence not actually needing a database connection on every request. Remember connecting to database is an expensive operation.

In the example below we will show you when you create a new Doctrine connection, the connection to the database isn’t created until it is actually needed.

// bootstrap.php
// At this point no actual connection to the database is created
$conn = Doctrine_Manager::connection('mysql://username:password@localhost/test');

// The first time the connection is needed, it is instantiated
// This query triggers the connection to be created
$conn->execute('SHOW TABLES');

Testing your Connection

After reading the previous sections of this chapter, you should now know how to create a connection. So, lets modify our bootstrap file to include the initialization of a connection. For this example we will just be using a sqlite memory database but you can use whatever type of database connection you prefer.

Add your database connection to bootstrap.php and it should look something like the following:

/* Bootstrap Doctrine.php, register autoloader and specify
   configuration attributes */

require_once('../doctrine/branches/1.2/lib/Doctrine.php');
spl_autoload_register(array('Doctrine', 'autoload'));
$manager = Doctrine_Manager::getInstance();

$conn = Doctrine_Manager::connection('sqlite::memory:', 'doctrine');

To test the connection lets modify our test.php script and perform a small test. Since we create a variable name $conn, that variable is available to the test script so lets setup a small test to make sure our connection is working:

First lets create a test table and insert a record:

// test.php
$conn->export->createTable('test', array('name' => array('type' => 'string')));
$conn->execute('INSERT INTO test (name) VALUES (?)', array('jwage'));

Now lets execute a simple SELECT query from the test table we just created to make sure the data was inserted and that we can retrieve it:

// test.php
$stmt = $conn->prepare('SELECT \* FROM test');
$stmt->execute();
$results = $stmt->fetchAll();
print_r($results);

Execute test.php from your terminal and you should see:

php test.php
Array(
  [0] => Array(
    [name] => jwage,
    [0] => jwage
  )
)

Conclusion

Great! Now we learned some basic operations of Doctrine connections. We have modified our Doctrine test environment to have a new connection. This is required because the examples in the coming chapters will require a connection.

Lets move on to the Configuration chapter and learn how you can control functionality and configurations using the Doctrine attribute system.

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