NAME

       HTML::FormHandler::Model - default model base class

VERSION

       version 0.40068

SYNOPSIS

       This class defines the base attributes for FormHandler model classes. It is not used
       directly.

DESCRIPTION

       This is an empty base class that defines methods called by HTML::FormHandler to support
       interfacing forms with a data store such as a database.

       This module provides instructions on methods to override to create a
       HTML::FormHandler::Model class to work with a specific object relational mapping (ORM)
       tool.

METHODS

   item, build_item
       The "item" is initialized with "build_item" the first time $form->item is called.  "item"
       must be defined in the model class to fetch the object based on the item id.  It should
       return the item's object.  Column values are fetched and updated by calling methods on the
       returned object.

       For example, with Class::DBI you might return:

           return $self->item_class->retrieve( $self->item_id );

   item_id
       The id (primary key) of the item (object) that the form is updating or has just created.
       The model class should have a build_item method that can fetch the object from the
       item_class for this id.

   item_class
       "item_class" sets and returns a value used by the model class to access the ORM class
       related to a form.

       For example:

          has '+item_class' => ( default => 'User' );

       This gives the model class a way to access the data store.  If this is not a fixed value
       (as above) then do not define the method in your subclass and instead set the value when
       the form is created:

           my $form = MyApp::Form::Users->new( item_class => $class );

       The value can be any scalar (or object) needed by the specific ORM to access the data
       related to the form.

       A builder for 'item_class' might be to return the class of the 'item'.

   guess_field_type
       Returns the guessed field type.  The field name is passed as the first argument.  This is
       only required if using "Auto" type of fields in your form classes.  You could override
       this in your form class, for example, if you use a field naming convention that indicates
       the field type.

       The metadata info about the columns can be used to assign types.

   lookup_options
       Retrieve possible options for a given select field from the database.  The default method
       returns undef.

       Returns an array reference of key/value pairs for the column passed in.  These values are
       used for the values and labels for field types that provide a list of options to select
       from (e.g. Select, Multiple).

       A 'Select' type field (or a field that inherits from HTML::FormHandler::Field::Select) can
       set a number of scalars that control how options are looked up:

           label_column()          - column that holds the label
           active_column()         - column that indicates if a row is acitve
           sort_column()           - column used for sorting the options

       The default for label_column is "name".

   validate_model
       Validates fields that are dependent on the model.  This is called via the validation
       process and the model class must at least validate "unique" constraints defined in the
       form class.

       Any errors on a field found should be set by calling the field's add_error method:

           $field->add_error('Value must be unique in the database');

       The default method does nothing.

   clear_model
       Clear out any dynamic data for persistent object

   update_model
       Update the model with validated fields

AUTHOR

       FormHandler Contributors - see HTML::FormHandler

COPYRIGHT AND LICENSE

       This software is copyright (c) 2017 by Gerda Shank.

       This is free software; you can redistribute it and/or modify it under the same terms as
       the Perl 5 programming language system itself.