Doc tweaks.

[dbsrgits/SQL-Translator.git] / lib / SQL / Translator / Schema / Field.pm

package SQL::Translator::Schema::Field;

# ----------------------------------------------------------------------
# $Id: Field.pm,v 1.16 2004-03-23 21:42:42 grommit Exp $
# ----------------------------------------------------------------------
# Copyright (C) 2002-4 SQLFairy Authors
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License as
# published by the Free Software Foundation; version 2.
#
# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
# 02111-1307  USA
# -------------------------------------------------------------------

=pod

=head1 NAME

SQL::Translator::Schema::Field - SQL::Translator field object

=head1 SYNOPSIS

  use SQL::Translator::Schema::Field;
  my $field = SQL::Translator::Schema::Field->new(
      name  => 'foo',
      table => $table,
  );

=head1 DESCRIPTION

C<SQL::Translator::Schema::Field> is the field object.

=head1 METHODS

=cut

use strict;
use Class::Base;
use SQL::Translator::Schema::Constants;
use SQL::Translator::Utils 'parse_list_arg';

use base 'Class::Base';
use vars qw($VERSION $TABLE_COUNT $VIEW_COUNT);

$VERSION = sprintf "%d.%02d", q$Revision: 1.16 $ =~ /(\d+)\.(\d+)/;

# Stringify to our name, being careful not to pass any args through so we don't
# accidentally set it to undef. We also have to tweak bool so the object is
# still true when it doesn't have a name (which shouldn't happen!).
use overload
    '""'     => sub { shift->name },
    'bool'   => sub { $_[0]->name || $_[0] },
    fallback => 1,
;

# ----------------------------------------------------------------------
sub init {

=pod

=head2 new

Object constructor.

  my $schema = SQL::Translator::Schema::Field->new(
  );

=cut

    my ( $self, $config ) = @_;

    for my $arg ( 
        qw[ 
            table name data_type size is_primary_key is_nullable
            is_auto_increment default_value comments
        ] 
    ) {
        next unless defined $config->{ $arg };
        defined $self->$arg( $config->{ $arg } ) or return;
    }

    return $self;
}

# ----------------------------------------------------------------------
sub comments {

=pod

=head2 comments

Get or set the comments on a field.  May be called several times to 
set and it will accumulate the comments.  Called in an array context,
returns each comment individually; called in a scalar context, returns
all the comments joined on newlines.

  $field->comments('foo');
  $field->comments('bar');
  print join( ', ', $field->comments ); # prints "foo, bar"

=cut

    my $self = shift;

    for my $arg ( @_ ) {
        $arg = $arg->[0] if ref $arg;
        push @{ $self->{'comments'} }, $arg if $arg;
    }

    if ( @{ $self->{'comments'} || [] } ) {
        return wantarray 
            ? @{ $self->{'comments'} || [] }
            : join( "\n", @{ $self->{'comments'} || [] } );
    }
    else {
        return wantarray ? () : '';
    }
}


# ----------------------------------------------------------------------
sub data_type {

=pod

=head2 data_type

Get or set the field's data type.

  my $data_type = $field->data_type('integer');

=cut

    my $self = shift;
    $self->{'data_type'} = shift if @_;
    return $self->{'data_type'} || '';
}

# ----------------------------------------------------------------------
sub default_value {

=pod

=head2 default_value

Get or set the field's default value.  Will return undef if not defined
and could return the empty string (it's a valid default value), so don't 
assume an error like other methods.

  my $default = $field->default_value('foo');

=cut

    my ( $self, $arg ) = @_;
    $self->{'default_value'} = $arg if defined $arg;
    return $self->{'default_value'};
}

# ----------------------------------------------------------------------
sub extra {

=pod

=head2 extra

Get or set the field's "extra" attibutes (e.g., "ZEROFILL" for MySQL).
Accepts a hash(ref) of name/value pairs to store;  returns a hash.

  $field->extra( qualifier => 'ZEROFILL' );
  my %extra = $field->extra;

=cut

    my $self = shift;
    my $args = ref $_[0] eq 'HASH' ? shift : { @_ };

    while ( my ( $key, $value ) = each %$args ) {
        $self->{'extra'}{ $key } = $value;
    }

    return %{ $self->{'extra'} || {} };
}

# ----------------------------------------------------------------------
sub foreign_key_reference {

=pod

=head2 foreign_key_reference

Get or set the field's foreign key reference;

  my $constraint = $field->foreign_key_reference( $constraint );

=cut

    my $self = shift;

    if ( my $arg = shift ) {
        my $class = 'SQL::Translator::Schema::Constraint';
        if ( UNIVERSAL::isa( $arg, $class ) ) {
            return $self->error(
                'Foreign key reference for ', $self->name, 'already defined'
            ) if $self->{'foreign_key_reference'};

            $self->{'foreign_key_reference'} = $arg;
        }
        else {
            return $self->error(
                "Argument to foreign_key_reference is not an $class object"
            );
        }
    }

    return $self->{'foreign_key_reference'};
}

# ----------------------------------------------------------------------
sub is_auto_increment {

=pod

=head2 is_auto_increment

Get or set the field's C<is_auto_increment> attribute.

  my $is_auto = $field->is_auto_increment(1);

=cut

    my ( $self, $arg ) = @_;

    if ( defined $arg ) {
        $self->{'is_auto_increment'} = $arg ? 1 : 0;
    }

    unless ( defined $self->{'is_auto_increment'} ) {
        if ( my $table = $self->table ) {
            if ( my $schema = $table->schema ) {
                if ( 
                    $schema->database eq 'PostgreSQL' &&
                    $self->data_type eq 'serial'
                ) {
                    $self->{'is_auto_increment'} = 1;
                }
            }
        }
    }

    return $self->{'is_auto_increment'} || 0;
}

# ----------------------------------------------------------------------
sub is_foreign_key {

=pod

=head2 is_foreign_key

Returns whether or not the field is a foreign key.

  my $is_fk = $field->is_foreign_key;

=cut

    my ( $self, $arg ) = @_;

    unless ( defined $self->{'is_foreign_key'} ) {
        if ( my $table = $self->table ) {
            for my $c ( $table->get_constraints ) {
                if ( $c->type eq FOREIGN_KEY ) {
                    my %fields = map { $_, 1 } $c->fields;
                    if ( $fields{ $self->name } ) {
                        $self->{'is_foreign_key'} = 1;
                        $self->foreign_key_reference( $c );
                        last;
                    }
                }
            }
        }
    }

    return $self->{'is_foreign_key'} || 0;
}

# ----------------------------------------------------------------------
sub is_nullable {

=pod

=head2 is_nullable

Get or set whether the field can be null.  If not defined, then 
returns "1" (assumes the field can be null).  The argument is evaluated
by Perl for True or False, so the following are eqivalent:

  $is_nullable = $field->is_nullable(0);
  $is_nullable = $field->is_nullable('');
  $is_nullable = $field->is_nullable('0');

While this is technically a field constraint, it's probably easier to
represent this as an attribute of the field.  In order keep things
consistent, any other constraint on the field (unique, primary, and
foreign keys; checks) are represented as table constraints.

=cut

    my ( $self, $arg ) = @_;

    if ( defined $arg ) {
        $self->{'is_nullable'} = $arg ? 1 : 0;
    }

    if ( 
        defined $self->{'is_nullable'} && 
        $self->{'is_nullable'} == 1    &&
        $self->is_primary_key
    ) {
        $self->{'is_nullable'} = 0;
    }

    return defined $self->{'is_nullable'} ? $self->{'is_nullable'} : 1;
}

# ----------------------------------------------------------------------
sub is_primary_key {

=pod

=head2 is_primary_key

Get or set the field's C<is_primary_key> attribute.  Does not create
a table constraint (should it?).

  my $is_pk = $field->is_primary_key(1);

=cut

    my ( $self, $arg ) = @_;

    if ( defined $arg ) {
        $self->{'is_primary_key'} = $arg ? 1 : 0;
    }

    unless ( defined $self->{'is_primary_key'} ) {
        if ( my $table = $self->table ) {
            if ( my $pk = $table->primary_key ) {
                my %fields = map { $_, 1 } $pk->fields;
                $self->{'is_primary_key'} = $fields{ $self->name } || 0;
            }
            else {
                $self->{'is_primary_key'} = 0;
            }
        }
    }

    return $self->{'is_primary_key'} || 0;
}

# ----------------------------------------------------------------------
sub is_unique {

=pod

=head2 is_unique

Determine whether the field has a UNIQUE constraint or not.

  my $is_unique = $field->is_unique;

=cut

    my $self = shift;
    
    unless ( defined $self->{'is_unique'} ) {
        if ( my $table = $self->table ) {
            for my $c ( $table->get_constraints ) {
                if ( $c->type eq UNIQUE ) {
                    my %fields = map { $_, 1 } $c->fields;
                    if ( $fields{ $self->name } ) {
                        $self->{'is_unique'} = 1;
                        last;
                    }
                }
            }
        }
    }

    return $self->{'is_unique'} || 0;
}

# ----------------------------------------------------------------------
sub is_valid {

=pod

=head2 is_valid

Determine whether the field is valid or not.

  my $ok = $field->is_valid;

=cut

    my $self = shift;
    return $self->error('No name')         unless $self->name;
    return $self->error('No data type')    unless $self->data_type;
    return $self->error('No table object') unless $self->table;
    return 1;
}

# ----------------------------------------------------------------------
sub name {

=pod

=head2 name

Get or set the field's name.

 my $name = $field->name('foo');

The field object will also stringify to its name.

 my $setter_name = "set_$field";

Errors ("No field name") if you try to set a blank name.

=cut

    my $self = shift;

    if ( @_ ) {
        my $arg = shift || return $self->error( "No field name" );
        if ( my $table = $self->table ) {
            return $self->error( qq[Can't use field name "$arg": field exists] )
                if $table->get_field( $arg );
        }

        $self->{'name'} = $arg;
    }

    return $self->{'name'} || '';
}

sub full_name {

=head2 full_name

Read only method to return the fields name with its table name pre-pended.
e.g. "person.foo".

=cut

    my $self = shift;
    return $self->table.".".$self->name;
}

# ----------------------------------------------------------------------
sub order {

=pod

=head2 order

Get or set the field's order.

  my $order = $field->order(3);

=cut

    my ( $self, $arg ) = @_;

    if ( defined $arg && $arg =~ /^\d+$/ ) {
        $self->{'order'} = $arg;
    }

    return $self->{'order'} || 0;
}

# ----------------------------------------------------------------------
sub size {

=pod

=head2 size

Get or set the field's size.  Accepts a string, array or arrayref of
numbers and returns a string.

  $field->size( 30 );
  $field->size( [ 255 ] );
  $size = $field->size( 10, 2 );
  print $size; # prints "10,2"

  $size = $field->size( '10, 2' );
  print $size; # prints "10,2"

=cut

    my $self    = shift;
    my $numbers = parse_list_arg( @_ );

    if ( @$numbers ) {
        my @new;
        for my $num ( @$numbers ) {
            if ( defined $num && $num =~ m/^\d+(?:\.\d+)?$/ ) {
                push @new, $num;
            }
        }
        $self->{'size'} = \@new if @new; # only set if all OK
    }

    return wantarray 
        ? @{ $self->{'size'} || [0] }
        : join( ',', @{ $self->{'size'} || [0] } )
    ;
}

# ----------------------------------------------------------------------
sub table {

=pod

=head2 table

Get or set the field's table object. As the table object stringifies this can
also be used to get the table name.

  my $table = $field->table;
  print "Table name: $table";

=cut

    my $self = shift;
    if ( my $arg = shift ) {
        return $self->error('Not a table object') unless
            UNIVERSAL::isa( $arg, 'SQL::Translator::Schema::Table' );
        $self->{'table'} = $arg;
    }

    return $self->{'table'};
}

# ----------------------------------------------------------------------
sub DESTROY {
#
# Destroy cyclical references.
#
    my $self = shift;
    undef $self->{'table'};
    undef $self->{'foreign_key_reference'};
}

1;

# ----------------------------------------------------------------------

=pod

=head1 AUTHOR

Ken Y. Clark E<lt>kclark@cpan.orgE<gt>.

=cut