Programming the Perl DBI

Name

connect

Synopsis

$dbh = DBI->connect($data_source, $username, $password)
          || die $DBI::errstr;
$dbh = DBI->connect($data_source, $username, $password, \%attr)
          || die $DBI::errstr;

connect establishes a database connection, or session, to the requested $data_source . Returns a database handle object if the connection succeeds. Use $dbh->disconnect to terminate the connection.

If the connect fails (see below), it returns undef and sets both $DBI::err and $DBI::errstr. (It does not set $!, etc.) You should generally test the return status of connect and print $DBI::errstr if it has failed.

Multiple simultaneous connections to multiple databases through multiple drivers can be made via the DBI. Simply make one connect call for each database and keep a copy of each returned database handle.

The $data_source value should begin with dbi: driver_name :. The driver_name specifies the driver that will be used to make the connection. (Letter case is significant.)

As a convenience, if the $data_source parameter is undefined or empty, the DBI will substitute the value of the environment variable DBI_DSN. If just the driver_name part is empty (i.e., the $data_source prefix is dbi::), the environment variable DBI_DRIVER is used. If neither variable is set, then connect dies.

Examples of $data_source values are:

dbi:DriverName:database_name
dbi:DriverName:database_name@hostname:port
dbi:DriverName:database=database_name;host=hostname;port=port

There is no standard for the text following the driver ...