=head1 NAME

Tangram::Type::Dump::Perl - map any Perl object as scalar dump 

=head1 SYNOPSIS

   use Tangram::Core;
   use Tangram::Type::Dump::Perl; # always

   $schema = Tangram::Schema->new(
      classes => { NaturalPerson => { fields => {

      perl_dump =>
      {
         diary => # diary is a perl hash 
         {
            col => 'diarydata',
            sql => 'TEXT',
            indent => 0,
            terse => 1,
            purity => 0
         },

         lucky_numbers => 'int', # use defaults
      }

=head1 DESCRIPTION

Maps arbitrary Perl data structures by serializing to a string
representation. The persistent fields are grouped in a hash under the
C<perl_dump> key in the field hash.

Serialization is done by L<Data::Dumper>, which traverses the Perl
data structure and creates a string representation of it. The
resulting string will be mapped to the DBMS as a scalar value. During
restore, the scalar value will be L<eval>'d to reconstruct the
original data structure. 

As of Tangram 2.07.1, persistent references are safely handled via the
L<Tangram::Type::Dump> utility class.

The field names are passed in a hash that associates a field name with
a field descriptor. The field descriptor may be either a hash or a
string. The hash uses the following fields:

=over 4

=item * col

=item * sql

=item * indent

=item * terse

=item * purity

=back

The optional fields C<col> and C<sql> specify the column name and the
column type for the scalar value in the database. If not present,
C<col> defaults to the field name and C<sql> defaults to VARCHAR(255).
Values will be always quoted as they are passed to the database.

The remaining optional fields control the serialization process. They
will be passed down to L<Data::Dumper> as values to the corresponding
L<Data::Dumper> options. The default settings are: no indentation
(C<indent=0>), compact format (C<terse=1>), and quick dump
(C<purity=0>).

=head1 AUTHOR

This mapping was contributed by Gabor Herr
<herr@iti.informatik.tu-darmstadt.de>
