PDO::__construct Creates a PDO instance to represent a connection to a database PDOPDO::__construct stringdsn stringusername stringpassword arraydriver_opts &warn.experimental.func; Creates a PDO instance to represent a connection to the requested database. The dsn parameter supports three different methods of specifying the arguments required to create a database connection: Driver invocation dsn consists of the PDO driver name, followed by a colon, followed by the PDO driver-specific connection syntax. For example, 'odbc:DSN=SAMPLE;UID=db2inst1;PWD=ibmdb2' would create a PDO_ODBC connection to an ODBC database, while 'mysql:host=127.0.0.1;dbname=testdb' would create a PDO_MYSQL connection to a MySQL database. 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. Aliasing dsn consists of a name name that maps to pdo.dsn.name in &php.ini; defining the DSN string. name can not contain a colon. If username or password are not required to complete the connection, you must pass empty strings or the constructor will throw a PDOException exception. getMessage(); } ?> ]]> 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: The PHP script can then create a database connection by simply passing the uri: parameter and pointing to the file URI: getMessage(); } ?> ]]> 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.dsn.mydb=mysql:dbname=testdb;host=127.0.0.1 getMessage(); } ?> ]]>