X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FDBIx%2FClass%2FStorage%2FDBI%2FSybase.pm;h=eeb4f01edf2a3806495f10925641a7d166d036b6;hb=6862815907d42aa2f5fcc70afd4ff2dbc9b48f79;hp=9cfc047aa729f1a25b4474e34d62cdfebbed7845;hpb=63d46bb3853faf51e05d39311c87b6aa7e44110d;p=dbsrgits%2FDBIx-Class.git

diff --git a/lib/DBIx/Class/Storage/DBI/Sybase.pm b/lib/DBIx/Class/Storage/DBI/Sybase.pm
index 9cfc047..eeb4f01 100644
--- a/lib/DBIx/Class/Storage/DBI/Sybase.pm
+++ b/lib/DBIx/Class/Storage/DBI/Sybase.pm
@@ -3,17 +3,65 @@ package DBIx::Class::Storage::DBI::Sybase;
 use strict;
 use warnings;
 
-use Class::C3;
-use base qw/DBIx::Class::Storage::DBI/;
-
+use base qw/
+    DBIx::Class::Storage::DBI::Sybase::Common
+    DBIx::Class::Storage::DBI::AutoCast
+/;
+use mro 'c3';
 use Carp::Clan qw/^DBIx::Class/;
+use List::Util();
+use Sub::Name();
+use Data::Dumper::Concise();
+
+__PACKAGE__->mk_group_accessors('simple' =>
+    qw/_identity _blob_log_on_update _writer_storage _is_extra_storage
+       _bulk_storage _is_bulk_storage _began_bulk_work
+       _bulk_disabled_due_to_coderef_connect_info_warned
+       _identity_method/
+);
+
+my @also_proxy_to_extra_storages = qw/
+  connect_call_set_auto_cast auto_cast connect_call_blob_setup
+  connect_call_datetime_setup
+
+  disconnect _connect_info _sql_maker _sql_maker_opts disable_sth_caching
+  auto_savepoint unsafe cursor_class debug debugobj schema
+/;
+
+=head1 NAME
+
+DBIx::Class::Storage::DBI::Sybase - Sybase support for DBIx::Class
+
+=head1 SYNOPSIS
+
+This subclass supports L<DBD::Sybase> for real Sybase databases.  If you are
+using an MSSQL database via L<DBD::Sybase>, your storage will be reblessed to
+L<DBIx::Class::Storage::DBI::Sybase::Microsoft_SQL_Server>.
+
+=head1 DESCRIPTION
+
+If your version of Sybase does not support placeholders, then your storage
+will be reblessed to L<DBIx::Class::Storage::DBI::Sybase::NoBindVars>. You can
+also enable that driver explicitly, see the documentation for more details.
+
+With this driver there is unfortunately no way to get the C<last_insert_id>
+without doing a C<SELECT MAX(col)>. This is done safely in a transaction
+(locking the table.) See L</INSERTS WITH PLACEHOLDERS>.
+
+A recommended L<DBIx::Class::Storage::DBI/connect_info> setting:
+
+  on_connect_call => [['datetime_setup'], ['blob_setup', log_on_update => 0]]
+
+=head1 METHODS
+
+=cut
 
 sub _rebless {
   my $self = shift;
 
   if (ref($self) eq 'DBIx::Class::Storage::DBI::Sybase') {
     my $dbtype = eval {
-      @{$self->dbh->selectrow_arrayref(qq{sp_server_info \@attribute_id=1})}[2]
+      @{$self->_get_dbh->selectrow_arrayref(qq{sp_server_info \@attribute_id=1})}[2]
     } || '';
 
     my $exception = $@;
@@ -23,45 +71,772 @@ sub _rebless {
     if (!$exception && $dbtype && $self->load_optional_class($subclass)) {
       bless $self, $subclass;
       $self->_rebless;
-    } else {
-      # real Sybase
-      if (not $self->dbh->{syb_dynamic_supported}) {
-        bless $self, 'DBIx::Class::Storage:DBI::Sybase::NoBindVars';
+    } else { # real Sybase
+      my $no_bind_vars = 'DBIx::Class::Storage::DBI::Sybase::NoBindVars';
+
+      if ($self->using_freetds) {
+        carp <<'EOF' unless $ENV{DBIC_SYBASE_FREETDS_NOWARN};
+
+You are using FreeTDS with Sybase.
+
+We will do our best to support this configuration, but please consider this
+support experimental.
+
+TEXT/IMAGE columns will definitely not work.
+
+You are encouraged to recompile DBD::Sybase with the Sybase Open Client libraries
+instead.
+
+See perldoc DBIx::Class::Storage::DBI::Sybase for more details.
+
+To turn off this warning set the DBIC_SYBASE_FREETDS_NOWARN environment
+variable.
+EOF
+        if (not $self->_typeless_placeholders_supported) {
+          if ($self->_placeholders_supported) {
+            $self->auto_cast(1);
+          } else {
+            $self->ensure_class_loaded($no_bind_vars);
+            bless $self, $no_bind_vars;
+            $self->_rebless;
+          }
+        }
+      }
+      elsif (not $self->_get_dbh->{syb_dynamic_supported}) {
+        # not necessarily FreeTDS, but no placeholders nevertheless
+        $self->ensure_class_loaded($no_bind_vars);
+        bless $self, $no_bind_vars;
         $self->_rebless;
+      } elsif (not $self->_typeless_placeholders_supported) {
+        # this is highly unlikely, but we check just in case
+        $self->auto_cast(1);
       }
-      $self->connect_call_datetime_setup;
-      $self->connect_call_blob_setup;
     }
   }
 }
 
+sub _init {
+  my $self = shift;
+  $self->_set_max_connect(256);
+
+  # based on LongReadLen in connect_info
+  $self->set_textsize if $self->using_freetds;
+
+# create storage for insert/(update blob) transactions,
+# unless this is that storage
+  return if $self->_is_extra_storage;
+
+  my $writer_storage = (ref $self)->new;
+
+  $writer_storage->_is_extra_storage(1);
+  $writer_storage->connect_info($self->connect_info);
+  $writer_storage->auto_cast($self->auto_cast);
+
+  $self->_writer_storage($writer_storage);
+
+# create a bulk storage unless connect_info is a coderef
+  return
+    if (Scalar::Util::reftype($self->_dbi_connect_info->[0])||'') eq 'CODE';
+
+  my $bulk_storage = (ref $self)->new;
+
+  $bulk_storage->_is_extra_storage(1);
+  $bulk_storage->_is_bulk_storage(1); # for special ->disconnect acrobatics
+  $bulk_storage->connect_info($self->connect_info);
+
+# this is why
+  $bulk_storage->_dbi_connect_info->[0] .= ';bulkLogin=1';
+
+  $self->_bulk_storage($bulk_storage);
+}
+
+for my $method (@also_proxy_to_extra_storages) {
+  no strict 'refs';
+  no warnings 'redefine';
+
+  my $replaced = __PACKAGE__->can($method);
+
+  *{$method} = Sub::Name::subname $method => sub {
+    my $self = shift;
+    $self->_writer_storage->$replaced(@_) if $self->_writer_storage;
+    $self->_bulk_storage->$replaced(@_)   if $self->_bulk_storage;
+    return $self->$replaced(@_);
+  };
+}
+
+sub disconnect {
+  my $self = shift;
+
+# Even though we call $sth->finish for uses off the bulk API, there's still an
+# "active statement" warning on disconnect, which we throw away here.
+# This is due to the bug described in insert_bulk.
+# Currently a noop because 'prepare' is used instead of 'prepare_cached'.
+  local $SIG{__WARN__} = sub {
+    warn $_[0] unless $_[0] =~ /active statement/i;
+  } if $self->_is_bulk_storage;
+
+# so that next transaction gets a dbh
+  $self->_began_bulk_work(0) if $self->_is_bulk_storage;
+
+  $self->next::method;
+}
+
+# Make sure we have CHAINED mode turned on if AutoCommit is off in non-FreeTDS
+# DBD::Sybase (since we don't know how DBD::Sybase was compiled.) If however
+# we're using FreeTDS, CHAINED mode turns on an implicit transaction which we
+# only want when AutoCommit is off.
 sub _populate_dbh {
   my $self = shift;
+
   $self->next::method(@_);
-  $self->connect_call_datetime_setup;
-  $self->connect_call_blob_setup;
-  1;
+  
+  if ($self->_is_bulk_storage) {
+# this should be cleared on every reconnect
+    $self->_began_bulk_work(0);
+    return;
+  }
+
+  if (not $self->using_freetds) {
+    $self->_dbh->{syb_chained_txn} = 1;
+  } else {
+    if ($self->_dbh_autocommit) {
+      $self->_dbh->do('SET CHAINED OFF');
+    } else {
+      $self->_dbh->do('SET CHAINED ON');
+    }
+  }
 }
 
 =head2 connect_call_blob_setup
 
 Used as:
 
-  on_connect_call => 'blob_setup'
+  on_connect_call => [ [ 'blob_setup', log_on_update => 0 ] ]
 
 Does C<< $dbh->{syb_binary_images} = 1; >> to return C<IMAGE> data as raw binary
 instead of as a hex string.
 
+Recommended.
+
+Also sets the C<log_on_update> value for blob write operations. The default is
+C<1>, but C<0> is better if your database is configured for it.
+
+See
+L<DBD::Sybase/Handling_IMAGE/TEXT_data_with_syb_ct_get_data()/syb_ct_send_data()>.
+
 =cut
 
 sub connect_call_blob_setup {
   my $self = shift;
+  my %args = @_;
   my $dbh = $self->_dbh;
   $dbh->{syb_binary_images} = 1;
+
+  $self->_blob_log_on_update($args{log_on_update})
+    if exists $args{log_on_update};
 }
 
-{
-  my $old_dbd_warned = 0;
+sub _is_lob_type {
+  my $self = shift;
+  my $type = shift;
+  $type && $type =~ /(?:text|image|lob|bytea|binary|memo)/i;
+}
+
+sub _is_lob_column {
+  my ($self, $source, $column) = @_;
+
+  return $self->_is_lob_type($source->column_info($column)->{data_type});
+}
+
+sub _prep_for_execute {
+  my $self = shift;
+  my ($op, $extra_bind, $ident, $args) = @_;
+
+  my ($sql, $bind) = $self->next::method (@_);
+
+  my $table = Scalar::Util::blessed($ident) ? $ident->from : $ident;
+
+  my $bind_info = $self->_resolve_column_info(
+    $ident, [map $_->[0], @{$bind}]
+  );
+  my $bound_identity_col = List::Util::first
+    { $bind_info->{$_}{is_auto_increment} }
+    (keys %$bind_info)
+  ;
+  my $identity_col = Scalar::Util::blessed($ident) &&
+    List::Util::first
+    { $ident->column_info($_)->{is_auto_increment} }
+    $ident->columns
+  ;
+
+  if (($op eq 'insert' && $bound_identity_col) ||
+      ($op eq 'update' && exists $args->[0]{$identity_col})) {
+    $sql = join ("\n",
+      $self->_set_table_identity_sql($op => $table, 'on'),
+      $sql,
+      $self->_set_table_identity_sql($op => $table, 'off'),
+    );
+  }
+
+  if ($op eq 'insert' && (not $bound_identity_col) && $identity_col &&
+      (not $self->{insert_bulk})) {
+    $sql =
+      "$sql\n" .
+      $self->_fetch_identity_sql($ident, $identity_col);
+  }
+
+  return ($sql, $bind);
+}
+
+sub _set_table_identity_sql {
+  my ($self, $op, $table, $on_off) = @_;
+
+  return sprintf 'SET IDENTITY_%s %s %s',
+    uc($op), $self->sql_maker->_quote($table), uc($on_off);
+}
+
+# Stolen from SQLT, with some modifications. This is a makeshift
+# solution before a sane type-mapping library is available, thus
+# the 'our' for easy overrides.
+our %TYPE_MAPPING  = (
+    number    => 'numeric',
+    money     => 'money',
+    varchar   => 'varchar',
+    varchar2  => 'varchar',
+    timestamp => 'datetime',
+    text      => 'varchar',
+    real      => 'double precision',
+    comment   => 'text',
+    bit       => 'bit',
+    tinyint   => 'smallint',
+    float     => 'double precision',
+    serial    => 'numeric',
+    bigserial => 'numeric',
+    boolean   => 'varchar',
+    long      => 'varchar',
+);
+
+sub _native_data_type {
+  my ($self, $type) = @_;
+
+  $type = lc $type;
+  $type =~ s/\s* identity//x;
+
+  return uc($TYPE_MAPPING{$type} || $type);
+}
+
+sub _fetch_identity_sql {
+  my ($self, $source, $col) = @_;
+
+  return sprintf ("SELECT MAX(%s) FROM %s",
+    map { $self->sql_maker->_quote ($_) } ($col, $source->from)
+  );
+}
+
+sub _execute {
+  my $self = shift;
+  my ($op) = @_;
+
+  my ($rv, $sth, @bind) = $self->dbh_do($self->can('_dbh_execute'), @_);
+
+  if ($op eq 'insert') {
+    $self->_identity($sth->fetchrow_array);
+    $sth->finish;
+  }
+
+  return wantarray ? ($rv, $sth, @bind) : $rv;
+}
+
+sub last_insert_id { shift->_identity }
+
+# handles TEXT/IMAGE and transaction for last_insert_id
+sub insert {
+  my $self = shift;
+  my ($source, $to_insert) = @_;
+
+  my $identity_col = (List::Util::first
+    { $source->column_info($_)->{is_auto_increment} }
+    $source->columns) || '';
+
+  # check for empty insert
+  # INSERT INTO foo DEFAULT VALUES -- does not work with Sybase
+  # try to insert explicit 'DEFAULT's instead (except for identity)
+  if (not %$to_insert) {
+    for my $col ($source->columns) {
+      next if $col eq $identity_col;
+      $to_insert->{$col} = \'DEFAULT';
+    }
+  }
+
+  my $blob_cols = $self->_remove_blob_cols($source, $to_insert);
+
+  # do we need the horrific SELECT MAX(COL) hack?
+  my $dumb_last_insert_id =
+       $identity_col
+    && (not exists $to_insert->{$identity_col})
+    && ($self->_identity_method||'') ne '@@IDENTITY';
+
+  my $next = $self->next::can;
+
+  # we are already in a transaction, or there are no blobs
+  # and we don't need the PK - just (try to) do it
+  if ($self->{transaction_depth}
+        || (!$blob_cols && !$dumb_last_insert_id) 
+  ) {
+    return $self->_insert (
+      $next, $source, $to_insert, $blob_cols, $identity_col
+    );
+  }
+
+  # otherwise use the _writer_storage to do the insert+transaction on another
+  # connection
+  my $guard = $self->_writer_storage->txn_scope_guard;
+
+  my $updated_cols = $self->_writer_storage->_insert (
+    $next, $source, $to_insert, $blob_cols, $identity_col
+  );
+
+  $self->_identity($self->_writer_storage->_identity);
+
+  $guard->commit;
+
+  return $updated_cols;
+}
+
+sub _insert {
+  my ($self, $next, $source, $to_insert, $blob_cols, $identity_col) = @_;
+
+  my $updated_cols = $self->$next ($source, $to_insert);
+
+  my $final_row = {
+    ($identity_col ?
+      ($identity_col => $self->last_insert_id($source, $identity_col)) : ()),
+    %$to_insert,
+    %$updated_cols,
+  };
+
+  $self->_insert_blobs ($source, $blob_cols, $final_row) if $blob_cols;
+
+  return $updated_cols;
+}
+
+sub update {
+  my $self = shift;
+  my ($source, $fields, $where, @rest) = @_;
+
+  my $wantarray = wantarray;
+
+  my $blob_cols = $self->_remove_blob_cols($source, $fields);
+
+  my $table = $source->name;
+
+  my $identity_col = List::Util::first
+    { $source->column_info($_)->{is_auto_increment} }
+    $source->columns;
+
+  my $is_identity_update = $identity_col && defined $fields->{$identity_col};
+
+  return $self->next::method(@_) unless $blob_cols;
+
+# If there are any blobs in $where, Sybase will return a descriptive error
+# message.
+# XXX blobs can still be used with a LIKE query, and this should be handled.
+
+# update+blob update(s) done atomically on separate connection
+  $self = $self->_writer_storage;
+
+  my $guard = $self->txn_scope_guard;
+
+# First update the blob columns to be updated to '' (taken from $fields, where
+# it is originally put by _remove_blob_cols .)
+  my %blobs_to_empty = map { ($_ => delete $fields->{$_}) } keys %$blob_cols;
+
+# We can't only update NULL blobs, because blobs cannot be in the WHERE clause.
+
+  $self->next::method($source, \%blobs_to_empty, $where, @rest);
+
+# Now update the blobs before the other columns in case the update of other
+# columns makes the search condition invalid.
+  $self->_update_blobs($source, $blob_cols, $where);
+
+  my @res;
+  if (%$fields) {
+    if ($wantarray) {
+      @res    = $self->next::method(@_);
+    }
+    elsif (defined $wantarray) {
+      $res[0] = $self->next::method(@_);
+    }
+    else {
+      $self->next::method(@_);
+    }
+  }
+
+  $guard->commit;
+
+  return $wantarray ? @res : $res[0];
+}
+
+sub insert_bulk {
+  my $self = shift;
+  my ($source, $cols, $data) = @_;
+
+  my $identity_col = List::Util::first
+    { $source->column_info($_)->{is_auto_increment} }
+    $source->columns;
+
+  my $is_identity_insert = (List::Util::first
+    { $_ eq $identity_col }
+    @{$cols}
+  ) ? 1 : 0;
+
+  my @source_columns = $source->columns;
+
+  my $use_bulk_api =
+    $self->_bulk_storage &&
+    $self->_get_dbh->{syb_has_blk};
+
+  if ((not $use_bulk_api) &&
+      (Scalar::Util::reftype($self->_dbi_connect_info->[0])||'') eq 'CODE' &&
+      (not $self->_bulk_disabled_due_to_coderef_connect_info_warned)) {
+    carp <<'EOF';
+Bulk API support disabled due to use of a CODEREF connect_info. Reverting to
+regular array inserts.
+EOF
+    $self->_bulk_disabled_due_to_coderef_connect_info_warned(1);
+  }
+
+  if (not $use_bulk_api) {
+    my $blob_cols = $self->_remove_blob_cols_array($source, $cols, $data);
+
+# _execute_array uses a txn anyway, but it ends too early in case we need to
+# select max(col) to get the identity for inserting blobs.
+    ($self, my $guard) = $self->{transaction_depth} == 0 ? 
+      ($self->_writer_storage, $self->_writer_storage->txn_scope_guard)
+      :
+      ($self, undef);
+
+    local $self->{insert_bulk} = 1;
+
+    $self->next::method(@_);
+
+    if ($blob_cols) {
+      if ($is_identity_insert) {
+        $self->_insert_blobs_array ($source, $blob_cols, $cols, $data);
+      }
+      else {
+        my @cols_with_identities = (@$cols, $identity_col);
+
+        ## calculate identities
+        # XXX This assumes identities always increase by 1, which may or may not
+        # be true.
+        my ($last_identity) =
+          $self->_dbh->selectrow_array (
+            $self->_fetch_identity_sql($source, $identity_col)
+          );
+        my @identities = (($last_identity - @$data + 1) .. $last_identity);
+
+        my @data_with_identities = map [@$_, shift @identities], @$data;
+
+        $self->_insert_blobs_array (
+          $source, $blob_cols, \@cols_with_identities, \@data_with_identities
+        );
+      }
+    }
+
+    $guard->commit if $guard;
+
+    return;
+  }
+
+# otherwise, use the bulk API
+
+# rearrange @$data so that columns are in database order
+  my %orig_idx;
+  @orig_idx{@$cols} = 0..$#$cols;
+
+  my %new_idx;
+  @new_idx{@source_columns} = 0..$#source_columns;
+
+  my @new_data;
+  for my $datum (@$data) {
+    my $new_datum = [];
+    for my $col (@source_columns) {
+# identity data will be 'undef' if not $is_identity_insert
+# columns with defaults will also be 'undef'
+      $new_datum->[ $new_idx{$col} ] =
+        exists $orig_idx{$col} ? $datum->[ $orig_idx{$col} ] : undef;
+    }
+    push @new_data, $new_datum;
+  }
+
+# bcp identity index is 1-based
+  my $identity_idx = exists $new_idx{$identity_col} ?
+    $new_idx{$identity_col} + 1 : 0;
+
+## Set a client-side conversion error handler, straight from DBD::Sybase docs.
+# This ignores any data conversion errors detected by the client side libs, as
+# they are usually harmless.
+  my $orig_cslib_cb = DBD::Sybase::set_cslib_cb(
+    Sub::Name::subname insert_bulk => sub {
+      my ($layer, $origin, $severity, $errno, $errmsg, $osmsg, $blkmsg) = @_;
+
+      return 1 if $errno == 36;
+
+      carp
+        "Layer: $layer, Origin: $origin, Severity: $severity, Error: $errno" .
+        ($errmsg ? "\n$errmsg" : '') .
+        ($osmsg  ? "\n$osmsg"  : '')  .
+        ($blkmsg ? "\n$blkmsg" : '');
+
+      return 0;
+  });
+
+  eval {
+    my $bulk = $self->_bulk_storage;
+
+    my $guard = $bulk->txn_scope_guard;
+
+## XXX get this to work instead of our own $sth
+## will require SQLA or *Hacks changes for ordered columns
+#    $bulk->next::method($source, \@source_columns, \@new_data, {
+#      syb_bcp_attribs => {
+#        identity_flag   => $is_identity_insert,
+#        identity_column => $identity_idx,
+#      }
+#    });
+    my $sql = 'INSERT INTO ' .
+      $bulk->sql_maker->_quote($source->name) . ' (' .
+# colname list is ignored for BCP, but does no harm
+      (join ', ', map $bulk->sql_maker->_quote($_), @source_columns) . ') '.
+      ' VALUES ('.  (join ', ', ('?') x @source_columns) . ')';
+
+## XXX there's a bug in the DBD::Sybase bulk support that makes $sth->finish for
+## a prepare_cached statement ineffective. Replace with ->sth when fixed, or
+## better yet the version above. Should be fixed in DBD::Sybase .
+    my $sth = $bulk->_get_dbh->prepare($sql,
+#      'insert', # op
+      {
+        syb_bcp_attribs => {
+          identity_flag   => $is_identity_insert,
+          identity_column => $identity_idx,
+        }
+      }
+    );
+
+    my @bind = do {
+      my $idx = 0;
+      map [ $_, $idx++ ], @source_columns;
+    };
+
+    $self->_execute_array(
+      $source, $sth, \@bind, \@source_columns, \@new_data, sub {
+        $guard->commit
+      }
+    );
+
+    $bulk->_query_end($sql);
+  };
+
+  my $exception = $@;
+  DBD::Sybase::set_cslib_cb($orig_cslib_cb);
+
+  if ($exception =~ /-Y option/) {
+    carp <<"EOF";
+
+Sybase bulk API operation failed due to character set incompatibility, reverting
+to regular array inserts:
+
+*** Try unsetting the LANG environment variable.
+
+$exception
+EOF
+    $self->_bulk_storage(undef);
+    unshift @_, $self;
+    goto \&insert_bulk;
+  }
+  elsif ($exception) {
+# rollback makes the bulkLogin connection unusable
+    $self->_bulk_storage->disconnect;
+    $self->throw_exception($exception);
+  }
+}
+
+sub _dbh_execute_array {
+  my ($self, $sth, $tuple_status, $cb) = @_;
+
+  my $rv = $self->next::method($sth, $tuple_status);
+  $cb->() if $cb;
+
+  return $rv;
+}
+
+# Make sure blobs are not bound as placeholders, and return any non-empty ones
+# as a hash.
+sub _remove_blob_cols {
+  my ($self, $source, $fields) = @_;
+
+  my %blob_cols;
+
+  for my $col (keys %$fields) {
+    if ($self->_is_lob_column($source, $col)) {
+      my $blob_val = delete $fields->{$col};
+      if (not defined $blob_val) {
+        $fields->{$col} = \'NULL';
+      }
+      else {
+        $fields->{$col} = \"''";
+        $blob_cols{$col} = $blob_val unless $blob_val eq '';
+      }
+    }
+  }
+
+  return %blob_cols ? \%blob_cols : undef;
+}
+
+# same for insert_bulk
+sub _remove_blob_cols_array {
+  my ($self, $source, $cols, $data) = @_;
+
+  my @blob_cols;
+
+  for my $i (0..$#$cols) {
+    my $col = $cols->[$i];
+
+    if ($self->_is_lob_column($source, $col)) {
+      for my $j (0..$#$data) {
+        my $blob_val = delete $data->[$j][$i];
+        if (not defined $blob_val) {
+          $data->[$j][$i] = \'NULL';
+        }
+        else {
+          $data->[$j][$i] = \"''";
+          $blob_cols[$j][$i] = $blob_val
+            unless $blob_val eq '';
+        }
+      }
+    }
+  }
+
+  return @blob_cols ? \@blob_cols : undef;
+}
+
+sub _update_blobs {
+  my ($self, $source, $blob_cols, $where) = @_;
+
+  my (@primary_cols) = $source->primary_columns;
+
+  $self->throw_exception('Cannot update TEXT/IMAGE column(s) without a primary key')
+    unless @primary_cols;
+
+# check if we're updating a single row by PK
+  my $pk_cols_in_where = 0;
+  for my $col (@primary_cols) {
+    $pk_cols_in_where++ if defined $where->{$col};
+  }
+  my @rows;
+
+  if ($pk_cols_in_where == @primary_cols) {
+    my %row_to_update;
+    @row_to_update{@primary_cols} = @{$where}{@primary_cols};
+    @rows = \%row_to_update;
+  } else {
+    my $cursor = $self->select ($source, \@primary_cols, $where, {});
+    @rows = map {
+      my %row; @row{@primary_cols} = @$_; \%row
+    } $cursor->all;
+  }
+
+  for my $row (@rows) {
+    $self->_insert_blobs($source, $blob_cols, $row);
+  }
+}
+
+sub _insert_blobs {
+  my ($self, $source, $blob_cols, $row) = @_;
+  my $dbh = $self->_get_dbh;
+
+  my $table = $source->name;
+
+  my %row = %$row;
+  my (@primary_cols) = $source->primary_columns;
+
+  $self->throw_exception('Cannot update TEXT/IMAGE column(s) without a primary key')
+    unless @primary_cols;
+
+  $self->throw_exception('Cannot update TEXT/IMAGE column(s) without primary key values')
+    if ((grep { defined $row{$_} } @primary_cols) != @primary_cols);
+
+  for my $col (keys %$blob_cols) {
+    my $blob = $blob_cols->{$col};
+
+    my %where = map { ($_, $row{$_}) } @primary_cols;
+
+    my $cursor = $self->select ($source, [$col], \%where, {});
+    $cursor->next;
+    my $sth = $cursor->sth;
+
+    if (not $sth) {
+
+      $self->throw_exception(
+          "Could not find row in table '$table' for blob update:\n"
+        . Data::Dumper::Concise::Dumper (\%where)
+      );
+    }
+
+    eval {
+      do {
+        $sth->func('CS_GET', 1, 'ct_data_info') or die $sth->errstr;
+      } while $sth->fetch;
+
+      $sth->func('ct_prepare_send') or die $sth->errstr;
+
+      my $log_on_update = $self->_blob_log_on_update;
+      $log_on_update    = 1 if not defined $log_on_update;
+
+      $sth->func('CS_SET', 1, {
+        total_txtlen => length($blob),
+        log_on_update => $log_on_update
+      }, 'ct_data_info') or die $sth->errstr;
+
+      $sth->func($blob, length($blob), 'ct_send_data') or die $sth->errstr;
+
+      $sth->func('ct_finish_send') or die $sth->errstr;
+    };
+    my $exception = $@;
+    $sth->finish if $sth;
+    if ($exception) {
+      if ($self->using_freetds) {
+        $self->throw_exception (
+          'TEXT/IMAGE operation failed, probably because you are using FreeTDS: '
+          . $exception
+        );
+      } else {
+        $self->throw_exception($exception);
+      }
+    }
+  }
+}
+
+sub _insert_blobs_array {
+  my ($self, $source, $blob_cols, $cols, $data) = @_;
+
+  for my $i (0..$#$data) {
+    my $datum = $data->[$i];
+
+    my %row;
+    @row{ @$cols } = @$datum;
+
+    my %blob_vals;
+    for my $j (0..$#$cols) {
+      if (exists $blob_cols->[$i][$j]) {
+        $blob_vals{ $cols->[$j] } = $blob_cols->[$i][$j];
+      }
+    }
+
+    $self->_insert_blobs ($source, \%blob_vals, \%row);
+  }
+}
 
 =head2 connect_call_datetime_setup
 
@@ -82,11 +857,15 @@ C<SMALLDATETIME> columns only have minute precision.
 
 =cut
 
+{
+  my $old_dbd_warned = 0;
+
   sub connect_call_datetime_setup {
     my $self = shift;
-    my $dbh = $self->_dbh;
+    my $dbh = $self->_get_dbh;
 
     if ($dbh->can('syb_date_fmt')) {
+      # amazingly, this works with FreeTDS
       $dbh->syb_date_fmt('ISO_strict');
     } elsif (not $old_dbd_warned) {
       carp "Your DBD::Sybase is too old to support ".
@@ -94,85 +873,259 @@ C<SMALLDATETIME> columns only have minute precision.
       $old_dbd_warned = 1;
     }
 
-    $dbh->do('set dateformat mdy');
+    $dbh->do('SET DATEFORMAT mdy');
 
     1;
   }
 }
 
-sub _dbh_last_insert_id {
-  my ($self, $dbh, $source, $col) = @_;
+sub datetime_parser_type { "DateTime::Format::Sybase" }
 
-  # sorry, there's no other way!
-  my $sth = $dbh->prepare_cached("select max($col) from ".$source->from);
-  return ($dbh->selectrow_array($sth))[0];
-}
+# ->begin_work and such have no effect with FreeTDS but we run them anyway to
+# let the DBD keep any state it needs to.
+#
+# If they ever do start working, the extra statements will do no harm (because
+# Sybase supports nested transactions.)
 
-sub count {
+sub _dbh_begin_work {
   my $self = shift;
-  my ($source, $attrs) = @_;
 
-  if (not exists $attrs->{rows}) {
-    return $self->next::method(@_);
+# bulkLogin=1 connections are always in a transaction, and can only call BEGIN
+# TRAN once. However, we need to make sure there's a $dbh.
+  return if $self->_is_bulk_storage && $self->_dbh && $self->_began_bulk_work;
+
+  $self->next::method(@_);
+
+  if ($self->using_freetds) {
+    $self->_get_dbh->do('BEGIN TRAN');
   }
 
-  my $offset = $attrs->{offset} || 0;
-  my $total  = $attrs->{rows} + $offset;
+  $self->_began_bulk_work(1) if $self->_is_bulk_storage;
+}
 
-  my $new_attrs = $self->_copy_attributes_for_count($source, $attrs);
+sub _dbh_commit {
+  my $self = shift;
+  if ($self->using_freetds) {
+    $self->_dbh->do('COMMIT');
+  }
+  return $self->next::method(@_);
+}
 
-  my $first_pk = ($source->primary_columns)[0];
+sub _dbh_rollback {
+  my $self = shift;
+  if ($self->using_freetds) {
+    $self->_dbh->do('ROLLBACK');
+  }
+  return $self->next::method(@_);
+}
 
-  $new_attrs->{select} = $first_pk ? "me.$first_pk" : 1;
+# savepoint support using ASE syntax
 
-  my $tmp_rs = $source->resultset_class->new($source, $new_attrs);
+sub _svp_begin {
+  my ($self, $name) = @_;
 
-  $self->dbh->{syb_rowcount} = $total;
+  $self->_get_dbh->do("SAVE TRANSACTION $name");
+}
 
-  my $count = 0;
-  $count++ while $tmp_rs->cursor->next;
+# A new SAVE TRANSACTION with the same name releases the previous one.
+sub _svp_release { 1 }
 
-  $self->dbh->{syb_rowcount} = 0;
+sub _svp_rollback {
+  my ($self, $name) = @_;
 
-  return $count - $offset;
+  $self->_get_dbh->do("ROLLBACK TRANSACTION $name");
 }
 
-sub datetime_parser_type { "DateTime::Format::Sybase" }
-
 1;
 
-=head1 NAME
+=head1 Schema::Loader Support
 
-DBIx::Class::Storage::DBI::Sybase - Storage::DBI subclass for Sybase
+There is an experimental branch of L<DBIx::Class::Schema::Loader> that will
+allow you to dump a schema from most (if not all) versions of Sybase.
 
-=head1 SYNOPSIS
+It is available via subversion from:
 
-This subclass supports L<DBD::Sybase> for real Sybase databases.  If you are
-using an MSSQL database via L<DBD::Sybase>, your storage will be reblessed to
-L<DBIx::Class::Storage::DBI::Sybase::Microsoft_SQL_Server>.
+  http://dev.catalyst.perl.org/repos/bast/branches/DBIx-Class-Schema-Loader/current/
 
-=head1 DESCRIPTION
+=head1 FreeTDS
 
-If your version of Sybase does not support placeholders, then your storage
-will be reblessed to L<DBIx::Class::Storage::DBI::Sybase::NoBindVars>. You can
-also enable that driver explicitly, see the documentation for more details.
+This driver supports L<DBD::Sybase> compiled against FreeTDS
+(L<http://www.freetds.org/>) to the best of our ability, however it is
+recommended that you recompile L<DBD::Sybase> against the Sybase Open Client
+libraries. They are a part of the Sybase ASE distribution:
 
-With this driver there is unfortunately no way to get the C<last_insert_id>
-without doing a C<select max(col)>.
+The Open Client FAQ is here:
+L<http://www.isug.com/Sybase_FAQ/ASE/section7.html>.
+
+Sybase ASE for Linux (which comes with the Open Client libraries) may be
+downloaded here: L<http://response.sybase.com/forms/ASE_Linux_Download>.
+
+To see if you're using FreeTDS check C<< $schema->storage->using_freetds >>, or run:
+
+  perl -MDBI -le 'my $dbh = DBI->connect($dsn, $user, $pass); print $dbh->{syb_oc_version}'
+
+Some versions of the libraries involved will not support placeholders, in which
+case the storage will be reblessed to
+L<DBIx::Class::Storage::DBI::Sybase::NoBindVars>.
+
+In some configurations, placeholders will work but will throw implicit type
+conversion errors for anything that's not expecting a string. In such a case,
+the C<auto_cast> option from L<DBIx::Class::Storage::DBI::AutoCast> is
+automatically set, which you may enable on connection with
+L<DBIx::Class::Storage::DBI::AutoCast/connect_call_set_auto_cast>. The type info
+for the C<CAST>s is taken from the L<DBIx::Class::ResultSource/data_type>
+definitions in your Result classes, and are mapped to a Sybase type (if it isn't
+already) using a mapping based on L<SQL::Translator>.
+
+In other configurations, placeholers will work just as they do with the Sybase
+Open Client libraries.
+
+Inserts or updates of TEXT/IMAGE columns will B<NOT> work with FreeTDS.
+
+=head1 INSERTS WITH PLACEHOLDERS
+
+With placeholders enabled, inserts are done in a transaction so that there are
+no concurrency issues with getting the inserted identity value using
+C<SELECT MAX(col)>, which is the only way to get the C<IDENTITY> value in this
+mode.
+
+In addition, they are done on a separate connection so that it's possible to
+have active cursors when doing an insert.
+
+When using C<DBIx::Class::Storage::DBI::Sybase::NoBindVars> transactions are
+disabled, as there are no concurrency issues with C<SELECT @@IDENTITY> as it's a
+session variable.
+
+=head1 TRANSACTIONS
 
-But your queries will be cached.
+Due to limitations of the TDS protocol, L<DBD::Sybase>, or both; you cannot
+begin a transaction while there are active cursors; nor can you use multiple
+active cursors within a transaction. An active cursor is, for example, a
+L<ResultSet|DBIx::Class::ResultSet> that has been executed using C<next> or
+C<first> but has not been exhausted or L<reset|DBIx::Class::ResultSet/reset>.
+
+For example, this will not work:
+
+  $schema->txn_do(sub {
+    my $rs = $schema->resultset('Book');
+    while (my $row = $rs->next) {
+      $schema->resultset('MetaData')->create({
+        book_id => $row->id,
+        ...
+      });
+    }
+  });
+
+This won't either:
+
+  my $first_row = $large_rs->first;
+  $schema->txn_do(sub { ... });
+
+Transactions done for inserts in C<AutoCommit> mode when placeholders are in use
+are not affected, as they are done on an extra database handle.
+
+Some workarounds:
+
+=over 4
+
+=item * use L<DBIx::Class::Storage::DBI::Replicated>
+
+=item * L<connect|DBIx::Class::Schema/connect> another L<Schema|DBIx::Class::Schema>
+
+=item * load the data from your cursor with L<DBIx::Class::ResultSet/all>
+
+=back
+
+=head1 MAXIMUM CONNECTIONS
+
+The TDS protocol makes separate connections to the server for active statements
+in the background. By default the number of such connections is limited to 25,
+on both the client side and the server side.
+
+This is a bit too low for a complex L<DBIx::Class> application, so on connection
+the client side setting is set to C<256> (see L<DBD::Sybase/maxConnect>.) You
+can override it to whatever setting you like in the DSN.
+
+See
+L<http://infocenter.sybase.com/help/index.jsp?topic=/com.sybase.help.ase_15.0.sag1/html/sag1/sag1272.htm>
+for information on changing the setting on the server side.
 
 =head1 DATES
 
 See L</connect_call_datetime_setup> to setup date formats
 for L<DBIx::Class::InflateColumn::DateTime>.
 
-=head1 IMAGE COLUMNS
+=head1 TEXT/IMAGE COLUMNS
+
+L<DBD::Sybase> compiled with FreeTDS will B<NOT> allow you to insert or update
+C<TEXT/IMAGE> columns.
+
+Setting C<< $dbh->{LongReadLen} >> will also not work with FreeTDS use either:
+
+  $schema->storage->dbh->do("SET TEXTSIZE $bytes");
+
+or
+
+  $schema->storage->set_textsize($bytes);
+
+instead.
+
+However, the C<LongReadLen> you pass in
+L<DBIx::Class::Storage::DBI/connect_info> is used to execute the equivalent
+C<SET TEXTSIZE> command on connection.
 
 See L</connect_call_blob_setup> for a L<DBIx::Class::Storage::DBI/connect_info>
 setting you need to work with C<IMAGE> columns.
 
-=head1 AUTHORS
+=head1 BULK API
+
+The experimental L<DBD::Sybase> Bulk API support is used for
+L<populate|DBIx::Class::ResultSet/populate> in B<void> context, in a transaction
+on a separate connection.
+
+To use this feature effectively, use a large number of rows for each
+L<populate|DBIx::Class::ResultSet/populate> call, eg.:
+
+  while (my $rows = $data_source->get_100_rows()) {
+    $rs->populate($rows);
+  }
+
+B<NOTE:> the L<add_columns|DBIx::Class::ResultSource/add_columns>
+calls in your C<Result> classes B<must> list columns in database order for this
+to work. Also, you may have to unset the C<LANG> environment variable before
+loading your app, if it doesn't match the character set of your database.
+
+When inserting IMAGE columns using this method, you'll need to use
+L</connect_call_blob_setup> as well.
+
+=head1 TODO
+
+=over
+
+=item *
+
+Transitions to AutoCommit=0 (starting a transaction) mode by exhausting
+any active cursors, using eager cursors.
+
+=item *
+
+Real limits and limited counts using stored procedures deployed on startup.
+
+=item *
+
+Adaptive Server Anywhere (ASA) support, with possible SQLA::Limit support.
+
+=item *
+
+Blob update with a LIKE query on a blob, without invalidating the WHERE condition.
+
+=item *
+
+bulk_insert using prepare_cached (see comments.)
+
+=back
+
+=head1 AUTHOR
 
 See L<DBIx::Class/CONTRIBUTORS>.