=pod

=head1 NAME

DBIx::Class::Schema::Loader::Manual::UpgradingFromV4 - Important Information
Related to Upgrading from Version 0.04006

=head1 What Changed

=over 4

=item *

add_column

The new Loader detects much more information about columns and sets flags like
C<is_auto_increment> that it didn't set before.

=item *

RelBuilder

The new RelBuilder will give you nicer accessor names for relationships, so you
will no longer have conflicts between a foreign key column and the relationship
accessor itself (if the FK is named C<_id>.)

It will also more correctly infer the relationship type, e.g. some relationships
that were previously detected as a C<has_many> will now be a C<might_have>
(when it detects a unique constraint on the foreign key column.)

Also C<cascade_delete> and C<cascade_copy> are turned off for by default for
C<has_many> and C<might_have> relationships, while C<belongs_to> relationships
are created with C<< on_delete => 'CASCADE' >> and C<< on_update => 'CASCADE' >>
by default. This is overridable via
L<relationship_attrs|DBIx::Class::Schema::Loader::Base/relationship_attrs>.

=item *

moniker_map

Table names are now singularized when determining the C<Result> class names. So
the table C<user_roles> would have become C<UserRoles> in C<0.04006> but now
becomes C<UserRole> instead.

=item *

use_namespaces

Now defaults to on. See L<DBIx::Class::Schema::Loader::Base/use_namespaces> and
L<DBIx::Class::Schema/"load_namespaces">.

=item *

Support for more databases

We now support Microsoft SQL Server and Sybase, and there are also many
improvements to the other backends.

=back

=head1 Backward Compatibility

In backward compatibility mode, the Loader will use the old relationship names
and types, will not singularize monikers for tables, and C<use_namespaces> will
be off.

To control this behavior see L<DBIx::Class::Schema::Loader::Base/naming> and
L<DBIx::Class::Schema::Loader::Base/use_namespaces>.

=head2 Static Schemas

When reading a C<Schema.pm> from a static schema generated with an C<0.04>
version of Loader, backward compatibility mode will default to on, unless
overridden with the C<naming> and/or C<use_namespaces> attributes.

=head2 Dynamic Schemas

Dynamic schemas will always by default use C<0.04006> mode and have
C<use_namespaces> off.

To upgrade a dynamic schema, set the C<naming> and C<use_namespaces> attributes
(which is proxied to the loader) in your C<Schema.pm>:

    __PACKAGE__->naming('current');
    __PACKAGE__->use_namespaces(1);

=head1 AUTHOR

See L<DBIx::Class::Schema::Loader/AUTHOR> and L<DBIx::Class::Schema::Loader/CONTRIBUTORS>.

=head1 LICENSE

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

=cut
