# get a prediction transcript adaptor from the database
  $pta = $database_adaptor->get_PredictionTranscriptAdaptor();

  # get a slice on a region of chromosome 1
  $sa = $database_adaptor->get_SliceAdaptor();

  $slice = $sa->fetch_by_region( 'chromosome', 'x', 100000, 200000 );

  # get all the prediction transcripts from the slice region
  $prediction_transcripts = @{ $pta->fetch_all_by_Slice($slice) };

  my $self = shift;

  return qw( pt.prediction_transcript_id
             pt.seq_region_id
             pt.seq_region_start
             pt.seq_region_end
             pt.seq_region_strand
             pt.analysis_id
             pt.display_label);

  my ($self, $sth, $mapper, $dest_slice) = @_;

  #
  # This code is ugly because an attempt has been made to remove as many
  # function calls as possible for speed purposes.  Thus many caches and
  # a fair bit of gymnastics is used.
  #

  my $sa = $self->db()->get_SliceAdaptor();
  my $aa = $self->db()->get_AnalysisAdaptor();

  my @ptranscripts;
  my %analysis_hash;
  my %slice_hash;
  my %sr_name_hash;
  my %sr_cs_hash;

  my ($prediction_transcript_id,
      $seq_region_id,
      $seq_region_start,
      $seq_region_end,
      $seq_region_strand,
      $analysis_id,
      $display_label);

  $sth->bind_columns(\$prediction_transcript_id,\$
                     seq_region_id,\$
                     seq_region_start,\$
                     seq_region_end,\$
                     seq_region_strand,\$
                     analysis_id,\$
                     display_label);

  my $asm_cs;
  my $cmp_cs;
  my $asm_cs_vers;
  my $asm_cs_name;
  my $cmp_cs_vers;
  my $cmp_cs_name;
  if($mapper) {
    $asm_cs = $mapper->assembled_CoordSystem();
    $cmp_cs = $mapper->component_CoordSystem();
    $asm_cs_name = $asm_cs->name();
    $asm_cs_vers = $asm_cs->version();
    $cmp_cs_name = $cmp_cs->name();
    $cmp_cs_vers = $cmp_cs->version();
  }

  my $dest_slice_start;
  my $dest_slice_end;
  my $dest_slice_strand;
  my $dest_slice_length;
  my $dest_slice_sr_name;
  my $dest_slice_sr_id;
  if($dest_slice) {
    $dest_slice_start  = $dest_slice->start();
    $dest_slice_end    = $dest_slice->end();
    $dest_slice_strand = $dest_slice->strand();
    $dest_slice_length = $dest_slice->length();
    $dest_slice_sr_name = $dest_slice->seq_region_name();
    $dest_slice_sr_id =  $dest_slice->get_seq_region_id();
  }

 FEATURE: while($sth->fetch()) {

    #get the analysis object
    my $analysis = $analysis_hash{$analysis_id} ||=
      $aa->fetch_by_dbID($analysis_id);
    #need to get the internal_seq_region, if present
    $seq_region_id = $self->get_seq_region_id_internal($seq_region_id);
    my $slice = $slice_hash{"ID:".$seq_region_id};

    if(!$slice) {
      $slice = $sa->fetch_by_seq_region_id($seq_region_id);
      $slice_hash{"ID:".$seq_region_id} = $slice;
      $sr_name_hash{$seq_region_id} = $slice->seq_region_name();
      $sr_cs_hash{$seq_region_id} = $slice->coord_system();
    }

    my $sr_name = $sr_name_hash{$seq_region_id};
    my $sr_cs   = $sr_cs_hash{$seq_region_id};
    #
    # remap the feature coordinates to another coord system 
    # if a mapper was provided
    #
    if($mapper) {

      ($seq_region_id,$seq_region_start,$seq_region_end,$seq_region_strand) =
        $mapper->fastmap($sr_name, $seq_region_start, $seq_region_end,
			 $seq_region_strand, $sr_cs);

      #skip features that map to gaps or coord system boundaries
      next FEATURE if(!defined($seq_region_id));

      #get a slice in the coord system we just mapped to
#      if($asm_cs == $sr_cs || ($cmp_cs != $sr_cs && $asm_cs->equals($sr_cs))) {
        $slice = $slice_hash{"ID:".$seq_region_id} ||=
          $sa->fetch_by_seq_region_id($seq_region_id);
#      } else {
#        $slice = $slice_hash{"NAME:$sr_name:$asm_cs_name:$asm_cs_vers"} ||=
#          $sa->fetch_by_region($asm_cs_name, $sr_name, undef, undef, undef,
#                               $asm_cs_vers);
#      }
    }

    #
    # If a destination slice was provided convert the coords
    # If the dest_slice starts at 1 and is foward strand, nothing needs doing
    #
    if($dest_slice) {
      if($dest_slice_start != 1 || $dest_slice_strand != 1) {
	if($dest_slice_strand == 1) {
	  $seq_region_start = $seq_region_start - $dest_slice_start + 1;
	  $seq_region_end   = $seq_region_end   - $dest_slice_start + 1;
	} else {
	  my $tmp_seq_region_start = $seq_region_start;
	  $seq_region_start = $dest_slice_end - $seq_region_end + 1;
	  $seq_region_end   = $dest_slice_end - $tmp_seq_region_start + 1;
	  $seq_region_strand *= -1;
	}
      }

      #throw away features off the end of the requested slice
      if($seq_region_end < 1 || $seq_region_start > $dest_slice_length ||
	( $dest_slice_sr_id ne $seq_region_id )) {
	next FEATURE;
      }


      $slice = $dest_slice;
    }

    # Finally, create the new PredictionTranscript.
    push( @ptranscripts,
          $self->_create_feature('Bio::EnsEMBL::PredictionTranscript', {
                                   '-start'    => $seq_region_start,
                                   '-end'      => $seq_region_end,
                                   '-strand'   => $seq_region_strand,
                                   '-adaptor'  => $self,
                                   '-slice'    => $slice,
                                   '-analysis' => $analysis,
                                   '-dbID' => $prediction_transcript_id,
                                   '-display_label' => $display_label
                                 } ) );

  }

  return\@ ptranscripts;

  my $self = shift;

  return ['prediction_transcript', 'pt'];
}


# _columns

#  Arg [1]    : none
#  Example    : none
#  Description: Implements abstract superclass method to define the columns
#               retrieved in database queries used to create prediction 
#               transcripts.
#  Returntype : list of strings
#  Exceptions : none
#  Caller     : generic_fetch
#

  my $self  = shift;
  my $slice = shift;
  my $logic_name = shift;
  my $load_exons = shift;

  my $transcripts = $self->SUPER::fetch_all_by_Slice($slice,$logic_name);

  # if there are 0 or 1 transcripts still do lazy-loading
  if(!$load_exons || @$transcripts < 2) {
    return $transcripts;
  }

  # preload all of the exons now, instead of lazy loading later
  # faster than 1 query per transcript

  # get extent of region spanned by transcripts
  my ($min_start, $max_end);
  foreach my $tr (@$transcripts) {
    if(!defined($min_start) || $tr->start() < $min_start) {
      $min_start = $tr->start();
    }
    if(!defined($max_end) || $tr->end() > $max_end) {
      $max_end   = $tr->end();
    }
  }

#  mades no sense, the limit for the slice will be defined by the transcripts
#  $min_start += $slice->start() - 1;
#  $max_end   += $slice->start() - 1;

  my $ext_slice;

  if($min_start >= $slice->start() && $max_end <= $slice->end()) {
    $ext_slice = $slice;
  } else {
    my $sa = $self->db()->get_SliceAdaptor();
    $ext_slice = $sa->fetch_by_region
      ($slice->coord_system->name(), $slice->seq_region_name(),
       $min_start,$max_end, $slice->strand(), $slice->coord_system->version());
  }

  # associate exon identifiers with transcripts

  my %tr_hash = map {$_->dbID => $_} @$transcripts;

  my $tr_id_str = '(' . join(',', keys %tr_hash) . ')';

  my $sth = $self->prepare
    ("SELECT prediction_transcript_id, prediction_exon_id, exon_rank " .
     "FROM   prediction_exon " .
     "WHERE  prediction_transcript_id IN $tr_id_str");

  $sth->execute();

  my ($ex_id, $tr_id, $rank);
  $sth->bind_columns(\$tr_id,\$ ex_id,\$ rank);

  my %ex_tr_hash;

  while($sth->fetch()) {
    $ex_tr_hash{$ex_id} ||= [];
    push @{$ex_tr_hash{$ex_id}}, [$tr_hash{$tr_id}, $rank];
  }

  $sth->finish();

  my $ea = $self->db()->get_PredictionExonAdaptor();
  my $exons = $ea->fetch_all_by_Slice($ext_slice);

  # move exons onto transcript slice, and add them to transcripts
  foreach my $ex (@$exons) {
    $ex = $ex->transfer($slice) if($slice != $ext_slice);

    if(!$ex) {
      throw("Unexpected. PredictionExon could not be transfered onto " .
            "PredictionTranscript slice.");
    }

    foreach my $row (@{$ex_tr_hash{$ex->dbID()}}) {
      my ($tr, $rank) = @$row;
      $tr->add_Exon($ex, $rank);
    }
  }

  return $transcripts;

  my $self = shift;
  my $stable_id = shift;

  throw('Stable_id argument expected') if(!$stable_id);

  my $syn = $self->_tables()->[1];

  $self->bind_param_generic_fetch($stable_id,SQL_VARCHAR);
  my $pts = $self->generic_fetch("$syn.display_label = ?");

  return (@$pts) ? $pts->[0] : undef;

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

   return $self->_list_dbIDs("prediction_transcript", undef, $ordered);
}

1;

  my $self = shift;
  my $pre_trans = shift;

  if(!ref($pre_trans)||!$pre_trans->isa('Bio::EnsEMBL::PredictionTranscript')){
    throw('Expected PredictionTranscript argument.');
  }

  if(!$pre_trans->is_stored($self->db())) {
    warning('PredictionTranscript is not stored in this DB - not removing.');
    return;
  }

  #remove all associated prediction exons
  my $pexon_adaptor = $self->db()->get_PredictionExonAdaptor();
  foreach my $pexon (@{$pre_trans->get_all_Exons}) {
    $pexon_adaptor->remove($pexon);
  }

  #remove the prediction transcript
  my $sth = $self->prepare( "DELETE FROM prediction_transcript
                             WHERE prediction_transcript_id = ?" );
  $sth->bind_param(1,$pre_trans->dbID,SQL_INTEGER);
  $sth->execute();

  #unset the adaptor and internal id
  $pre_trans->dbID(undef);
  $pre_trans->adaptor(undef);

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

  my $ptstore_sth = $self->prepare
    (qq{INSERT INTO prediction_transcript (seq_region_id, seq_region_start,
                                           seq_region_end, seq_region_strand, 
                                           analysis_id, display_label)
        VALUES( ?, ?, ?, ?, ?, ?)});

  my $ptupdate_sth = $self->prepare
    (qq{UPDATE prediction_transcript SET display_label = ?
        WHERE  prediction_transcript_id = ?});

  my $db = $self->db();
  my $analysis_adaptor = $db->get_AnalysisAdaptor();
  my $pexon_adaptor = $db->get_PredictionExonAdaptor();

  FEATURE: foreach my $pt (@pre_transcripts) {
    if(!ref($pt) || !$pt->isa('Bio::EnsEMBL::PredictionTranscript')) {
      throw('Expected PredictionTranscript argument not [' . ref($pt).']');
    }

    #skip prediction transcripts that have already been stored
    if($pt->is_stored($db)) {
      warning('Not storing already stored prediction transcript '. $pt->dbID);
      next FEATURE;
    }

    #get analysis and store it if it is not in the db
    my $analysis = $pt->analysis();
    if(!$analysis) {
      throw('Prediction transcript must have analysis to be stored.');
    }
    if(!$analysis->is_stored($db)) {
      $analysis_adaptor->store($analysis);
    }

    #ensure that the transcript coordinates are correct, they may not be,
    #if somebody has done some exon coordinate juggling and not recalculated
    #the transcript coords.
    $pt->recalculate_coordinates();

    my $original = $pt;
    my $seq_region_id;
    ($pt, $seq_region_id) = $self->_pre_store($pt);

    #store the prediction transcript
    $ptstore_sth->bind_param(1,$seq_region_id,SQL_INTEGER);
    $ptstore_sth->bind_param(2,$pt->start,SQL_INTEGER);
    $ptstore_sth->bind_param(3,$pt->end,SQL_INTEGER);
    $ptstore_sth->bind_param(4,$pt->strand,SQL_TINYINT);
    $ptstore_sth->bind_param(5,$analysis->dbID,SQL_INTEGER);
    $ptstore_sth->bind_param(6,$pt->display_label,SQL_VARCHAR);

    $ptstore_sth->execute();

    my $pt_id = $ptstore_sth->{'mysql_insertid'};
    $original->dbID($pt_id);
    $original->adaptor($self);

    #store the exons
    my $rank = 1;
    foreach my $pexon (@{$original->get_all_Exons}) {
      $pexon_adaptor->store($pexon, $pt_id, $rank++);
    }

    # if a display label was not defined autogenerate one
    if(!defined($pt->display_label())) {
      my $zeros = '0' x (11 - length($pt_id));
      my $display_label = uc($analysis->logic_name()) . $zeros . $pt_id;
      $ptupdate_sth->bind_param(1,$display_label,SQL_VARCHAR);
      $ptupdate_sth->bind_param(2,$pt_id,SQL_INTEGER);
      $ptupdate_sth->execute();
      $original->display_label($display_label);
    }
  }

  Copyright (c) 1999-2009 The European Bioinformatics Institute and
  Genome Research Limited.  All rights reserved.

  This software is distributed under a modified Apache license.
  For license details, please see

    /info/about/code_licence.html

  Please email comments or questions to the public Ensembl
  developers list at <ensembl-dev@ebi.ac.uk>.

  Questions may also be sent to the Ensembl help desk at
  <helpdesk@ensembl.org>.