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 http://www.php.net/manual/en/function.PDO-construct.php. The DSN consists in the following parts: 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 option: Additional connection options in URI query string format. options get separated by &. The Following table shows a non complete list of options: name 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 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 database backends are: 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) oci8 -> Oracle 7/8/9/10 pgsql -> PostgreSQL? querysim -> QuerySim? sqlite -> SQLite 2 A second DSN format is supported 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: : = %3a / = %2f @ = %40 + = %2b ( = %28 ) = %29 ? = %3f = = %3d & = %26 Please note, that some features may be not supported by all database backends. mysql://user@unix(/path/to/socket)/pear pgsql://user:pass@tcp(localhost:5555)/pear sqlite:////full/unix/path/to/file.db?mode=0666 sqlite:///c:/full/windows/path/to/file.db?mode=0666 mysqli://user:pass@localhost/pear?key=client-key.pem&cert=client-cert.pem Opening a new database connection in Doctrine is very easy. If you wish to use PDO (www.php.net/PDO) you can just initalize a new PDO object: getMessage(); } ?>]]> If your database extension isn't supported by PDO you can use special Doctrine_Adapter class (if availible). The following example uses DB2 adapter: getMessage(); } ?>]]> The next step is opening a new Doctrine_Connection. ]]> Lazy-connecting to database is handled via Doctrine_Db wrapper. When using Doctrine_Db instead of PDO / Doctrine_Adapter, lazy-connecting to database is being performed (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. query('FROM User u'); ?>]]> From the start Doctrine has been designed to work with multiple connections. Unless separately specified Doctrine always uses the current connection for executing the queries. The following example uses openConnection() second argument as an optional connection alias. openConnection(new PDO('dsn','username','password'), 'connection 1'); ?>]]> For convenience Doctrine_Manager provides static method connection() which opens new connection when arguments are given to it and returns the current connection when no arguments have been speficied. ]]> The current connection is the lastly opened connection. openConnection(new PDO('dsn2','username2','password2'), 'connection 2'); $manager->getCurrentConnection(); // $conn2 ?>]]> You can change the current connection by calling setCurrentConnection(). setCurrentConnection('connection 1'); $manager->getCurrentConnection(); // $conn ?>]]> You can iterate over the opened connection by simple passing the manager object to foreach clause. This is possible since Doctrine_Manager implements special IteratorAggregate interface. ]]> Doctrine allows you to bind connections to components (= your ActiveRecord? classes). This means everytime a component issues a query or data is being fetched from the table the component is pointing at Doctrine will use the bound connection. openConnection(new PDO('dsn','username','password'), 'connection 1'); $conn2 = $manager->openConnection(new PDO('dsn2','username2','password2'), 'connection 2'); $manager->bindComponent('User', 'connection 1'); $manager->bindComponent('Group', 'connection 2'); $q = new Doctrine_Query(); // Doctrine uses 'connection 1' for fetching here $users = $q->from('User u')->where('u.id IN (1,2,3)')->execute(); // Doctrine uses 'connection 2' for fetching here $groups = $q->from('Group g')->where('g.id IN (1,2,3)')->execute(); ?>]]>