NAME

       Data::ObjectDriver::Driver::SimplePartition - basic partitioned object driver

SYNOPSIS

           package ParentObject;
           use base qw( Data::ObjectDriver::BaseObject );

           __PACKAGE__->install_properties({
               columns     => [ 'parent_id', 'partition_id', ... ],
               ...
               driver      => Data::ObjectDriver::Driver::DBI->new( @$GLOBAL_DB_INFO ),
               primary_key => 'parent_id',
           });

           __PACKAGE__->has_partitions(
               number     => scalar @PARTITIONS,
               get_driver => \&get_driver_by_partition,
           );

           package SomeObject;
           use base qw( Data::ObjectDriver::BaseObject );

           __PACKAGE__->install_properties({
               ...
               driver               => Data::ObjectDriver::Driver::SimplePartition->new(
                                           using => 'ParentObject'
                                       ),
               primary_key          => ['parent_id', 'object_id'],
           });

DESCRIPTION

       Data::ObjectDriver::Driver::SimplePartition is a basic driver for objects partitioned into
       separate databases. See Data::ObjectDriver::Driver::Partition for more about partitioning
       databases.

       SimplePartition helps you partition objects into databases based on their association with
       one record of a parent class. If your classes don't meet the requirements imposed by
       SimplePartition, you can still write your own partitioning driver. See
       Data::ObjectDriver::Driver::Partition.

SUGGESTED PRACTICES

       Often this is used for user partitioning, where the parent class is your user account
       class; all records of other classes that are "owned" by that user are partitioned into the
       same database. This allows you to scale horizontally with the number of users, at the cost
       of complicating querying multiple users' data together.

       SimplePartition will load the related instance of the parent class every time it needs to
       find the partition for a related object. Consider using a minimal mapping class for the
       parent, keeping as much data as possible in other related classes. For example, if "User"
       were your parent class, you might keep only the user ID and other data used to find users
       (such as login name and email address) in "User", keeping further profile data in another
       "UserProfile" class.

       As all the partitioned classes related to a given parent class will share the same
       "partition_get_driver" logic to turn a partition ID into a driver, you might put the
       "partition_get_driver" function in the parent class, or use a custom subclass of
       SimplePartition that contains and automatically specifies the "partition_get_driver"
       function.

USAGE

   Data::ObjectDriver::Driver::SimplePartition->new(%params)
       Creates a new basic partitioning driver for a particular class. The required members of
       %params are:

       •   "using"

           The name of the parent class on which the driven class is partitioned.

           Using a class as a parent partitioned class requires these properties to be defined:

           •   "columns"

               The parent class must have a "partition_id" column containing a partition
               identifier. This identifier is passed to the "partition_get_driver" function to
               identify a driver to return.

           •   "primary_key"

               The parent class's primary key must be a simple single-column key, and that column
               must be the same as the referencing column in the partitioned classes.

           •   "partition_get_driver"

               The "partition_get_driver" property must be a function that returns an object
               driver, given a partition ID and any extra parameters given to the
               "SimplePartition" constructor.

               This property can also be defined as "get_driver" in a call to
               "Class->has_partitions()". See Data::ObjectDriver::BaseObject.

       You can also include any further optional parameters you like. They will be passed to the
       partitioned class's "partition_get_driver" function as given.

       A SimplePartition driver will require these properties to be defined for partitioned
       classes:

       •   "primary_key"

           Your primary key should be a complex primary key (arrayref) with the simple key of the
           parent object for the first field.

DIAGNOSTICS

       •   "using is required."

           The "using" parameter to the SimplePartition constructor is required to create the
           partitioned class's "get_driver" function. Perhaps you omitted it, or your subclass of
           SimplePartition did not properly specify it to its parent's constructor.

       •   "Bogus classname."

           The parent class name you specified in your "using" parameter does not appear to be a
           valid class name. If you are automatically generating parent class names, check that
           your method of converting strings to class names is correct.

       •   "Failed to load parent class: error"

           The parent class you specified in your "using" parameter could not be loaded, for the
           given reason. Perhaps you didn't include its location in your library path.

       •   "Partitioning driver not defined for partitioned class"

           The partitioned class named in the error is configured to use the SimplePartition
           driver but does not have a "partition_get_driver" set.  Check that you intended to use
           SimplePartition with that class or, if you're automatically specifying the
           "partition_get_driver" function, that your technique is working correctly.

       •   "Cannot extract column from terms search terms or primary key"

           The SimplePartition driver could not determine from the given search terms or object
           key what the ID of the related parent record was. Check that your columns in the
           partitioned and parent classes share the same name, and that your application includes
           the parent ID in all "search()" calls for the partitioned class and instances of
           partitioned objects before attempting to save them.

           Optionaly you can enable a basic support of search accross multiple partition by
           passing the 'multi_partition' arg (true value) to the search query.

       •   "Member of class with ID parent ID not found"

           The parent record associated with the partitioned object could not be loaded.  Perhaps
           your application deleted the parent record without removing its associated partitioned
           objects first.

BUGS AND LIMITATIONS

       There are no known bugs in this module.

SEE ALSO

       Data::ObjectDriver::Driver::Partition

LICENSE

       Data::ObjectDriver is free software; you may redistribute it and/or modify it under the
       same terms as Perl itself.

AUTHOR & COPYRIGHT

       Except where otherwise noted, Data::ObjectDriver is Copyright 2005-2006 Six Apart,
       cpan@sixapart.com. All rights reserved.

perl v5.12.4                                2010-Data::ObjectDriver::Driver::SimplePartition(3pm)