PDO::__construct Creates a PDO instance representing a connection to a database &reftitle.description; PDOPDO::__construct stringdsn stringusername stringpassword arraydriver_options &warn.experimental.func; Creates a PDO instance to represent a connection to the requested database. &reftitle.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. 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: 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. 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. &reftitle.returnvalues; Returns a PDO object on success. &reftitle.exceptions; PDO::construct throws a PDOException if the attempt to connect to the requested database fails. &reftitle.examples; 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] pdo.dsn.mydb="mysql:dbname=testdb;host=localhost" getMessage(); } ?> ]]>