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lib/DB/Object/Constraint/Foreign.pm  view on Meta::CPAN

sub match { return( shift->_set_get_scalar_as_object( 'match', @_ ) ); }

sub name { return( shift->_set_get_scalar_as_object( 'name', @_ ) ); }

sub on_delete { return( shift->_set_get_scalar_as_object( 'on_delete', @_ ) ); }

sub on_update { return( shift->_set_get_scalar_as_object( 'on_update', @_ ) ); }

sub table { return( shift->_set_get_scalar_as_object( 'table', @_ ) ); }

# NOTE: For CBOR and Sereal
sub FREEZE
{
    my $self       = CORE::shift( @_ );
    my $serialiser = CORE::shift( @_ ) // '';
    my $class      = CORE::ref( $self );

    my @props = qw(
        expr fields match on_deete on_update name table
    );

    my $hash = {};
    foreach my $prop ( @props )
    {
        if( CORE::exists( $self->{ $prop } ) &&
            defined( $self->{ $prop } ) &&
            CORE::ref( $self->{ $prop } ) ne 'CODE' )
        {
            $hash->{ $prop } = $self->{ $prop };
        }
    }

    # Return an array reference rather than a list so this works with Sereal and CBOR.
    # Before Sereal version 4.023, Sereal did not support multiple values returned.
    if( $serialiser eq 'Sereal' )
    {
        require Sereal::Encoder;
        require version;

        if( version->parse( Sereal::Encoder->VERSION ) < version->parse( '4.023' ) )
        {
            CORE::return( [$class, $hash] );
        }
    }

    # But Storable wants a list with the first element being the serialised element
    CORE::return( $class, $hash );
}

sub STORABLE_freeze { return( shift->FREEZE( @_ ) ); }

sub STORABLE_thaw { return( shift->THAW( @_ ) ); }

sub STORABLE_thaw_post_processing
{
    my $obj   = shift( @_ );
    my @keys  = %$obj;
    my $class = ref( $obj );
    my $hash  = {};
    @$hash{ @keys } = @$obj{ @keys };
    my $self = bless( $hash => $class );
    return( $self );
}

sub THAW
{
    # STORABLE_thaw would issue $cloning as the 2nd argument, while CBOR would issue
    # 'CBOR' as the second value.
    my( $self, undef, @args ) = @_;
    my $ref   = ( CORE::scalar( @args ) == 1 && CORE::ref( $args[0] ) eq 'ARRAY' ) ? CORE::shift( @args ) : \@args;
    my $class = ( CORE::defined( $ref ) && CORE::ref( $ref ) eq 'ARRAY' && CORE::scalar( @$ref ) > 1 ) ? CORE::shift( @$ref ) : ( CORE::ref( $self ) || $self );
    my $hash = CORE::ref( $ref ) eq 'ARRAY' ? CORE::shift( @$ref ) : {};
    my $new;
    # Storable pattern requires to modify the object it created rather than returning a new one
    if( CORE::ref( $self ) )
    {
        foreach( CORE::keys( %$hash ) )
        {
            $self->{ $_ } = CORE::delete( $hash->{ $_ } );
        }
        $new = $self;
    }
    else
    {
        $new = CORE::bless( $hash => $class );
    }
    CORE::return( $new );
}

1;
# NOTE: POD
__END__

=encoding utf-8

=head1 NAME

DB::Object::Constraint::Foreign - Table Foreign Key Constraint Class

=head1 SYNOPSIS

    use DB::Object::Constraint::Foreign;
    my $foreign = DB::Object::Constraint::Foreign->new(
        expr => q{FOREIGN KEY (lang) REFERENCES language(lang) ON DELETE RESTRICT},
        fields => [qw( lang )],
        match => 'simple',
        on_delete => 'restrict',
        on_update => 'nothing',
        name => 'fk_user_info_lang',
        table => 'language',
    ) || die( DB::Object::Constraint::Foreign->error, "\n" );

=head1 VERSION

    v0.2.0

=head1 DESCRIPTION

This class represents a table foreign key constraint. It is instantiated by the L<structure|DB::Object::Tables/structure> method when retrieving the table structure details.

=head1 CONSTRUCTOR

=head2 new

To instantiate new object, you can pass an hash or hash reference of properties matching the method names available below.

=head1 METHODS

=head2 expr

Sets or gets the foreign key constraint expression.

It returns a L<scalar object|Module::Generic::Scalar>

=head2 fields

Sets or gets an array reference of table field names associated with this constraint.

It returns a L<array object|Module::Generic::Array>

=head2 match

Sets or gets the method a foreign key constraint matches.

For example: C<full>, C<partial> and C<simple>