X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FDBIx%2FClass%2FStorage%2FDBI%2FSybase.pm;h=6c0736983c77fa8e1b621be7425b8411ef208c84;hb=c9d9c67046115c4717b9ad49532b66d82d135310;hp=cc8a0cc51bf0ed08a49d94490b27c04b173b57da;hpb=9b3dabe0c35b6dafdfec559d594e95d5131e84b5;p=dbsrgits%2FDBIx-Class.git

diff --git a/lib/DBIx/Class/Storage/DBI/Sybase.pm b/lib/DBIx/Class/Storage/DBI/Sybase.pm
index cc8a0cc..6c07369 100644
--- a/lib/DBIx/Class/Storage/DBI/Sybase.pm
+++ b/lib/DBIx/Class/Storage/DBI/Sybase.pm
@@ -4,15 +4,20 @@ use strict;
 use warnings;
 
 use base qw/
-    DBIx::Class::Storage::DBI::Sybase::Base
-    DBIx::Class::Storage::DBI
+    DBIx::Class::Storage::DBI::Sybase::Common
+    DBIx::Class::Storage::DBI::AutoCast
 /;
 use mro 'c3';
 use Carp::Clan qw/^DBIx::Class/;
+use List::Util ();
+
+__PACKAGE__->mk_group_accessors('simple' =>
+    qw/_identity _blob_log_on_update unsafe_insert _insert_dbh/
+);
 
 =head1 NAME
 
-DBIx::Class::Storage::DBI::Sybase - Storage::DBI subclass for Sybase
+DBIx::Class::Storage::DBI::Sybase - Sybase support for DBIx::Class
 
 =head1 SYNOPSIS
 
@@ -27,28 +32,27 @@ 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)>.
+without doing a C<SELECT MAX(col)>. This is done safely in a transaction
+(locking the table.) The transaction can be turned off if concurrency is not an
+issue, or you don't need the C<IDENTITY> value, see
+L<DBIx::Class::Storage::DBI::Sybase/connect_call_unsafe_insert>.
 
 But your queries will be cached.
 
-A recommended L<DBIx::Class::Storage::DBI/connect_info> settings:
+A recommended L<DBIx::Class::Storage::DBI/connect_info> setting:
 
-  on_connect_call => [['datetime_setup'], [blob_setup => log_on_update => 0]]
+  on_connect_call => [['datetime_setup'], ['blob_setup', log_on_update => 0]]
 
 =head1 METHODS
 
 =cut
 
-__PACKAGE__->mk_group_accessors('simple' =>
-    qw/_blob_log_on_update/
-);
-
 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 = $@;
@@ -58,38 +62,82 @@ sub _rebless {
     if (!$exception && $dbtype && $self->load_optional_class($subclass)) {
       bless $self, $subclass;
       $self->_rebless;
-    } else {
-      # real Sybase
-      if (not $self->dbh->{syb_dynamic_supported}) {
-        $self->ensure_class_loaded('DBIx::Class::Storage::DBI::Sybase::NoBindVars');
-        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;
+          }
+        }
+
+        $self->set_textsize; # based on LongReadLen in connect_info
+
+      }
+      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->_set_maxConnect;
+
+      $self->_set_max_connect(256);
     }
   }
 }
 
-sub _set_maxConnect {
+# 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;
 
-  my $dsn = $self->_dbi_connect_info->[0];
-
-  return if ref($dsn) eq 'CODE';
+  $self->next::method(@_);
 
-  if ($dsn !~ /maxConnect=/) {
-    $self->_dbi_connect_info->[0] = "$dsn;maxConnect=256";
-    my $connected = defined $self->_dbh;
-    $self->disconnect;
-    $self->ensure_connected if $connected;
+  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');
+    }
   }
+
+  $self->_insert_dbh($self->_connect(@{ $self->_dbi_connect_info }));
 }
 
 =head2 connect_call_blob_setup
 
 Used as:
 
-  on_connect_call => [ [ blob_setup => log_on_update => 0 ] ]
+  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.
@@ -114,43 +162,204 @@ sub connect_call_blob_setup {
     if exists $args{log_on_update};
 }
 
+=head2 connect_call_unsafe_insert
+
+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)> when placeholders are enabled.
+
+When using C<DBIx::Class::Storage::DBI::Sybase::NoBindVars> transactions are
+disabled.
+
+To turn off transactions for inserts (for an application that doesn't need
+concurrency, or a loader, for example) use this setting in
+L<DBIx::Class::Storage::DBI/connect_info>,
+
+  on_connect_call => ['unsafe_insert']
+
+To manipulate this setting at runtime, use:
+
+  $schema->storage->unsafe_insert(0|1);
+
+=cut
+
+sub connect_call_unsafe_insert {
+  my $self = shift;
+  $self->unsafe_insert(1);
+}
+
 sub _is_lob_type {
   my $self = shift;
-  shift =~ /(?:text|image|lob|bytea|binary)/i;
+  my $type = shift;
+  $type && $type =~ /(?:text|image|lob|bytea|binary|memo)/i;
 }
 
+sub _prep_for_execute {
+  my $self = shift;
+  my ($op, $extra_bind, $ident, $args) = @_;
+
+  my ($sql, $bind) = $self->next::method (@_);
+
+  if ($op eq 'insert') {
+    my $table = $ident->from;
+
+    my $bind_info = $self->_resolve_column_info(
+      $ident, [map $_->[0], @{$bind}]
+    );
+    my $identity_col = List::Util::first
+      { $bind_info->{$_}{is_auto_increment} }
+      (keys %$bind_info)
+    ;
+
+    if ($identity_col) {
+      $sql = join ("\n",
+        "SET IDENTITY_INSERT $table ON",
+        $sql,
+        "SET IDENTITY_INSERT $table OFF",
+      );
+    }
+    else {
+      $identity_col = List::Util::first
+        { $ident->column_info($_)->{is_auto_increment} }
+        $ident->columns
+      ;
+    }
+
+    if ($identity_col) {
+      $sql =
+        "$sql\n" .
+        $self->_fetch_identity_sql($ident, $identity_col);
+    }
+  }
+
+  return ($sql, $bind);
+}
+
+# Stolen from SQLT, with some modifications. This is a makeshift
+# solution before a sane type-mapping library is available, thus
+# the 'our' for easy overrides.
+our %TYPE_MAPPING  = (
+    number    => 'numeric',
+    money     => 'money',
+    varchar   => 'varchar',
+    varchar2  => 'varchar',
+    timestamp => 'datetime',
+    text      => 'varchar',
+    real      => 'double precision',
+    comment   => 'text',
+    bit       => 'bit',
+    tinyint   => 'smallint',
+    float     => 'double precision',
+    serial    => 'numeric',
+    bigserial => 'numeric',
+    boolean   => 'varchar',
+    long      => 'varchar',
+);
+
+sub _native_data_type {
+  my ($self, $type) = @_;
+
+  $type = lc $type;
+  $type =~ s/\s* identity//x;
+
+  return uc($TYPE_MAPPING{$type} || $type);
+}
+
+sub _fetch_identity_sql {
+  my ($self, $source, $col) = @_;
+
+  return "SELECT MAX($col) FROM ".$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, $source, $to_insert) = splice @_, 0, 3;
+  my $self = shift;
+  my ($source, $to_insert) = @_;
 
   my $blob_cols = $self->_remove_blob_cols($source, $to_insert);
 
-  my $updated_cols = $self->next::method($source, $to_insert, @_);
+# insert+blob insert done atomically
+  my $guard = $self->txn_scope_guard if $blob_cols;
+
+  my $need_last_insert_id = 0;
+
+  my ($identity_col) =
+    map $_->[0],
+    grep $_->[1]{is_auto_increment},
+    map [ $_, $source->column_info($_) ],
+    $source->columns;
+
+  $need_last_insert_id = 1
+    if $identity_col && (not exists $to_insert->{$identity_col});
+
+  # We have to do the insert in a transaction to avoid race conditions with the
+  # SELECT MAX(COL) identity method used when placeholders are enabled.
+  my $updated_cols = do {
+    if (
+      $need_last_insert_id && !$self->unsafe_insert && !$self->{transaction_depth}
+    ) {
+      local $self->{_dbh} = $self->_insert_dbh;
+      my $guard = $self->txn_scope_guard;
+      my $upd_cols = $self->next::method (@_);
+      $guard->commit;
+      $upd_cols;
+    }
+    else {
+      $self->next::method(@_);
+    }
+  };
+
+  $self->_insert_blobs($source, $blob_cols, $to_insert) if $blob_cols;
 
-  $self->_update_blobs($source, $blob_cols, $to_insert) if %$blob_cols;
+  $guard->commit if $guard;
 
   return $updated_cols;
 }
 
-#sub update {
-#  my ($self, $source) = splice @_, 0, 2;
-#  my ($fields)        = @_;
-#
-#  my $blob_cols = $self->_remove_blob_cols($source, $fields);
-#
-#  my @res = 1;
-#
-#  if (%$fields) {
-#    if (wantarray) {
-#      @res    = $self->next::method($source, @_);
-#    } else {
-#      $res[0] = $self->next::method($source, @_);
-#    }
-#  }
-#
-#  $self->_update_blobs($source, $blob_cols, $fields) if %$blob_cols;
-#
-#  return wantarray ? @res : $res[0];
-#}
+sub update {
+  my $self = shift;
+  my ($source, $fields, $where) = @_;
+
+  my $wantarray = wantarray;
+
+  my $blob_cols = $self->_remove_blob_cols($source, $fields);
+
+# update+blob update(s) done atomically
+  my $guard = $self->txn_scope_guard if $blob_cols;
+
+  my @res;
+  if ($wantarray) {
+    @res    = $self->next::method(@_);
+  }
+  elsif (defined $wantarray) {
+    $res[0] = $self->next::method(@_);
+  }
+  else {
+    $self->next::method(@_);
+  }
+
+  $self->_update_blobs($source, $blob_cols, $where) if $blob_cols;
+
+  $guard->commit if $guard;
+
+  return $wantarray ? @res : $res[0];
+}
 
 sub _remove_blob_cols {
   my ($self, $source, $fields) = @_;
@@ -164,25 +373,60 @@ sub _remove_blob_cols {
     }
   }
 
-  return \%blob_cols;
+  return keys %blob_cols ? \%blob_cols : undef;
 }
 
 sub _update_blobs {
-  my ($self, $source, $blob_cols, $inserted) = @_;
-  my $dbh = $self->dbh;
+  my ($self, $source, $blob_cols, $where) = @_;
+
+  my (@primary_cols) = $source->primary_columns;
+
+  croak "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 $rs = $source->resultset->search(
+      $where,
+      {
+        result_class => 'DBIx::Class::ResultClass::HashRefInflator',
+        select => \@primary_cols
+      }
+    );
+    @rows = $rs->all; # statement must finish
+  }
+
+  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->from;
 
-  my %inserted = %$inserted;
+  my %row = %$row;
   my (@primary_cols) = $source->primary_columns;
 
   croak "Cannot update TEXT/IMAGE column(s) without a primary key"
     unless @primary_cols;
 
-  if ((grep { defined $inserted{$_} } @primary_cols) != @primary_cols) {
+  if ((grep { defined $row{$_} } @primary_cols) != @primary_cols) {
     if (@primary_cols == 1) {
       my $col = $primary_cols[0];
-      $inserted{$col} = $self->last_insert_id($source, $col);
+      $row{$col} = $self->last_insert_id($source, $col);
     } else {
       croak "Cannot update TEXT/IMAGE column(s) without primary key values";
     }
@@ -190,28 +434,19 @@ sub _update_blobs {
 
   for my $col (keys %$blob_cols) {
     my $blob = $blob_cols->{$col};
-    my $sth;
 
-    if (not $self->isa('DBIx::Class::Storage::DBI::NoBindVars')) {
-      my $search_cond = join ',' => map "$_ = ?", @primary_cols;
-
-      $sth = $self->sth(
-        "select $col from $table where $search_cond"
-      );
-      $sth->execute(map $inserted{$_}, @primary_cols);
-    } else {
-      my $search_cond = join ',' => map "$_ = $inserted{$_}", @primary_cols;
-
-      $sth = $dbh->prepare(
-        "select $col from $table where $search_cond"
-      );
-      $sth->execute;
-    }
+    my %where = map { ($_, $row{$_}) } @primary_cols;
+    my $cursor = $source->resultset->search(\%where, {
+      select => [$col]
+    })->cursor;
+    $cursor->next;
+    my $sth = $cursor->sth;
 
     eval {
-      while ($sth->fetch) {
+      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;
@@ -227,8 +462,17 @@ sub _update_blobs {
       $sth->func('ct_finish_send') or die $sth->errstr;
     };
     my $exception = $@;
-    $sth->finish;
-    croak $exception if $exception;
+    $sth->finish if $sth;
+    if ($exception) {
+      if ($self->using_freetds) {
+        croak (
+          'TEXT/IMAGE operation failed, probably because you are using FreeTDS: '
+          . $exception
+        );
+      } else {
+        croak $exception;
+      }
+    }
   }
 }
 
@@ -259,6 +503,7 @@ C<SMALLDATETIME> columns only have minute precision.
     my $dbh = $self->_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 ".
@@ -266,7 +511,7 @@ C<SMALLDATETIME> columns only have minute precision.
       $old_dbd_warned = 1;
     }
 
-    $dbh->do('set dateformat mdy');
+    $dbh->do('SET DATEFORMAT mdy');
 
     1;
   }
@@ -274,25 +519,140 @@ C<SMALLDATETIME> columns only have minute precision.
 
 sub datetime_parser_type { "DateTime::Format::Sybase" }
 
-sub _dbh_last_insert_id {
-  my ($self, $dbh, $source, $col) = @_;
+# ->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 _dbh_begin_work {
+  my $self = shift;
+  $self->next::method(@_);
+  if ($self->using_freetds) {
+    $self->_get_dbh->do('BEGIN TRAN');
+  }
+}
+
+sub _dbh_commit {
+  my $self = shift;
+  if ($self->using_freetds) {
+    $self->_dbh->do('COMMIT');
+  }
+  return $self->next::method(@_);
+}
+
+sub _dbh_rollback {
+  my $self = shift;
+  if ($self->using_freetds) {
+    $self->_dbh->do('ROLLBACK');
+  }
+  return $self->next::method(@_);
+}
+
+# savepoint support using ASE syntax
 
-  # sorry, there's no other way!
-  my $sth = $dbh->prepare_cached("select max($col) from ".$source->from);
-  return ($dbh->selectrow_array($sth))[0];
+sub _svp_begin {
+  my ($self, $name) = @_;
+
+  $self->_get_dbh->do("SAVE TRANSACTION $name");
+}
+
+# A new SAVE TRANSACTION with the same name releases the previous one.
+sub _svp_release { 1 }
+
+sub _svp_rollback {
+  my ($self, $name) = @_;
+
+  $self->_get_dbh->do("ROLLBACK TRANSACTION $name");
 }
 
 1;
 
+=head1 Schema::Loader Support
+
+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.
+
+It is available via subversion from:
+
+  http://dev.catalyst.perl.org/repos/bast/branches/DBIx-Class-Schema-Loader/current/
+
+=head1 FreeTDS
+
+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:
+
+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 TRANSACTIONS
+
+Due to limitations of the TDS protocol, L<DBD::Sybase>, or both; you cannot
+begin a transaction while there are active cursors. 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>.
+
+Transactions done for inserts in C<AutoCommit> mode when placeholders are in use
+are also affected, so this won't work:
+
+  while (my $row = $rs1->next) {
+    $rs2->create({ foo => $row->foo });
+  }
+
+Some workarounds:
+
+=over 4
+
+=item * set C<< $schema->storage->unsafe_insert(1) >> temporarily (see
+L</connect_call_unsafe_insert>)
+
+=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>
+
+=item * enlarge the scope of the transaction
+
+=back
+
 =head1 MAXIMUM CONNECTIONS
 
-L<DBD::Sybase> 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.
+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, so on connection the clientside setting is set to C<256>
-(see L<DBD::Sybase/maxConnect>.) You can override it to whatever setting you
-like in the DSN.
+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>
@@ -303,15 +663,29 @@ for information on changing the setting on the server side.
 See L</connect_call_datetime_setup> to setup date formats
 for L<DBIx::Class::InflateColumn::DateTime>.
 
-=head1 IMAGE AND TEXT 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.
 
-Due to limitations in L<DBD::Sybase> and this driver, it is only possible to
-select one C<TEXT> or C<IMAGE> column at a time.
-
-=head1 AUTHORS
+=head1 AUTHOR
 
 See L<DBIx::Class/CONTRIBUTORS>.