CGI::Application::Plugin::DBH(3pm)			User Contributed Perl Documentation			CGI::Application::Plugin::DBH(3pm)

NAME

       CGI::Application::Plugin::DBH - Easy DBI access from CGI::Application

SYNOPSIS

	use CGI::Application::Plugin::DBH (qw/dbh_config dbh/);

	sub cgiapp_init  {
	   my $self = shift;

	   # use the same args as DBI->connect();
	   $self->dbh_config($data_source, $username, $auth, \%attr);

	   # or to use more than one dbh
	   $self->dbh_config('my_handle',
			   [ $data_source, $user, $auth, \%attr ]);
	   $self->dbh_config('my_other_handle',
			   [ $data_source, $user, $auth, \%attr ]);
	}

	sub my_run_mode {
	   my $self = shift;

	   my $date = $self->dbh->selectrow_array("SELECT CURRENT_DATE");
	   # again with a named handle
	   $date = $self->dbh('my_handle')->selectrow_array("SELECT CURRENT_DATE");

	   # OR ...

	   my $dbh = $self->dbh;
	   # again with a named handle
	   $dbh = $self->dbh('my_other_handle');
	   my $date = $dbh->selectrow_array("SELECT CURRENT_DATE");
	}

DESCRIPTION

       CGI::Application::Plugin::DBH adds easy access to a DBI database handle to your CGI::Application modules.  Lazy loading is used to prevent
       a database connection from being made if the "dbh" method is not called during the request.  In other words, the database connection is not
       created until it is actually needed.

METHODS

   dbh()
	my $date = $self->dbh->selectrow_array("SELECT CURRENT_DATE");
	# again with a named handle
	$date = $self->dbh('my_handle')->selectrow_array("SELECT CURRENT_DATE");

	# OR ...

	my $dbh = $self->dbh;
	# again with a named handle
	$dbh = $self->dbh('my_other_handle');
	my $date = $dbh->selectrow_array("SELECT CURRENT_DATE");

       This method will return the current DBI database handle.  The database handle is created on the first call to this method, and any
       subsequent calls will return the same handle.

   dbh_config()
	sub cgiapp_init  {
	   my $self = shift;

	   # use the same args as DBI->connect();
	   $self->dbh_config($data_source, $username, $auth, \%attr);

	   # or to use more than one dbh
	   $self->dbh_config('my_handle',
			   [ $data_source, $user, $auth, \%attr ]);
	   $self->dbh_config('my_other_handle',
			   [ $data_source, $user, $auth, \%attr ]);

	   # ...or use some existing handle you have
	   $self->dbh_config($DBH);
	   $self->dbh_config('my_handle', $DBH);   # this works too

	   # Use a callback to create your owh handle that is still lazy loaded
	   $self->dbh_config(sub { DBI->connect_cached(); });
	}

       Used to provide your DBI connection parameters. You can either pass in an existing DBI database handle, or provide the usual parameters
       used for DBI->connect().

       The recommended place to call "dbh_config" is in the "cgiapp_init" stage of CGI::Application.  If this method is called after the database
       handle has already been accessed, then it will die with an error message.

       Automatic configuration using CGI::App instance parameters

       An alternative to explicitly calling "dbh_config" in your application is to rely on the presence of specific instance parameters that allow
       the plugin to configure itself.

       If you set the CGI::App parameter "::Plugin::DBH::dbh_config" to an array reference the contents of that array will be used as parameters
       to "dbh_config" (if it has not been explicitly called before).

       The code in the synopsis can be rewritten as

	 use CGI::Application::Plugin::DBH (qw/dbh/);
	       # no longer a need to import dbh_config

	 sub cgiapp_init  {
	    # you do not need to do anything here
	 }

	 sub my_run_mode {

	       # this part stays unchanged

	       ....

	 }

       and in the instance script ( or instance configuration file, if you have)

	  $app->param('::Plugin::DBH::dbh_config' =>
		       [ $data_source, $username, $auth, \%attr ] );

       If you want to configure more than one handle, set up a hash with the handle names as keys:

	       $app->param('::Plugin::DBH::dbh_config' =>
		       { my_handle => [ $data_source, $username, $auth, \%attr ] ,
			 my_other_handle => [ $data_source, $username, $auth, \%attr ]
		       }  );

       Automatic configuration with DBI environment variables

       If you do not set any parameters, and do not call "dbh_config", this plugin checks to see if you set the DBI environment variable
       "DBI_DSN". If present, this DSN will be used for the default handle. Note that the DBI documentation does not encourage using this method
       (especially in the context of web applications), that you will most likely have to also set "DBI_USER" and "DBI_PASS", and that this can
       only be used for the default handle.

   dbh_default_name()
	sub my_runmode {
	   my $self = shift;

	   my $old_handle_name = $self->dbh_default_name('my_handle');
	   $self->some_legacy_code();  # some_legacy_code() will get "my_handle"
				       # when it calls $self->dbh() without parameters

	   $self->dbh_default_name($old_handle_name);	 # Return to normal.
	}

       Can be used to alter the name of the handle that is returned by dbh() when called with no parameters. It can even be used to alter the name
       used for the unamed handle if called before dbh_config().

       Using this method is completely optional. If you don't have a use for it don't use it. Internally the handle name
       "__cgi_application_plugin_dbh" is used to keep track of the unnamed handle unless it is changed by dbh_default_name() before a call to
       dbh_config() without a name parameter.

SEE ALSO

       Ima::DBI is similar, but has much more complexity and features.

       CGI::Application, DBI, CGI::Application::Plugin::ValidateRM, perl(1)

AUTHOR

       Mark Stosberg <mark@summersault.com>

       Multi Handle Support added by: Tony Fraser <tony@sybaspace.com>

       Autoconfig Support added by: Thilo Planz <thilo@cpan.org>

LICENSE

       Copyright (C) 2004 Mark Stosberg <mark@summersault.com>

       This library is free software. You can modify and or distribute it under the same terms as Perl itself.

perl v5.12.3							    2011-06-26					CGI::Application::Plugin::DBH(3pm)