X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FDBIx%2FClass%2FStorage%2FDBI%2FSybase.pm;h=9851303d6a384d024080e48651600a51e7700fad;hb=689819e14e9e6245000c64ece46ddd1bc8293bf5;hp=05cc32a5cf39b300a442a961c8bab0825971cb00;hpb=fd42320593c173596f9ee869ec7c4b65cfe4b745;p=dbsrgits%2FDBIx-Class.git diff --git a/lib/DBIx/Class/Storage/DBI/Sybase.pm b/lib/DBIx/Class/Storage/DBI/Sybase.pm index 05cc32a..9851303 100644 --- a/lib/DBIx/Class/Storage/DBI/Sybase.pm +++ b/lib/DBIx/Class/Storage/DBI/Sybase.pm @@ -2,16 +2,32 @@ package DBIx::Class::Storage::DBI::Sybase; use strict; use warnings; -use mro 'c3'; + 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 (); +use Sub::Name (); + +__PACKAGE__->mk_group_accessors('simple' => + qw/_identity _blob_log_on_update _writer_storage _is_writer_storage + _identity_method/ +); + +my @also_proxy_to_writer_storage = 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 - Storage::DBI subclass for Sybase +DBIx::Class::Storage::DBI::Sybase - Sybase support for DBIx::Class =head1 SYNOPSIS @@ -26,28 +42,23 @@ will be reblessed to L. 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 -without doing a C. This is done safely in a transaction +(locking the table.) See L. -A recommended L settings: +A recommended L 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 = $@; @@ -57,21 +68,108 @@ sub _rebless { if (!$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); } } } } +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_writer_storage; + + my $writer_storage = (ref $self)->new; + + $writer_storage->_is_writer_storage(1); + $writer_storage->connect_info($self->connect_info); + $writer_storage->auto_cast($self->auto_cast); + + $self->_writer_storage($writer_storage); +} + +for my $method (@also_proxy_to_writer_storage) { + no strict 'refs'; + no warnings 'redefine'; + + my $replaced = __PACKAGE__->can($method); + + *{$method} = Sub::Name::subname __PACKAGE__."::$method" => sub { + my $self = shift; + $self->_writer_storage->$replaced(@_) if $self->_writer_storage; + return $self->$replaced(@_); + }; +} + +# 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(@_); + + 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 => log_on_update => 0 ] ] + on_connect_call => [ [ 'blob_setup', log_on_update => 0 ] ] Does C<< $dbh->{syb_binary_images} = 1; >> to return C data as raw binary instead of as a hex string. @@ -98,88 +196,401 @@ sub connect_call_blob_setup { sub _is_lob_type { my $self = shift; - shift =~ /(?:text|image|lob|bytea|binary)/i; + my $type = shift; + $type && $type =~ /(?:text|image|lob|bytea|binary|memo)/i; +} + +sub _is_lob_column { + my ($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) = $self->next::method (@_); + + if ($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 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, $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, @_); + my $identity_col = List::Util::first + { $source->column_info($_)->{is_auto_increment} } + $source->columns; + + # 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); - $self->_update_blobs($source, $blob_cols, $to_insert) if %$blob_cols; + $guard->commit; 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 : $res[0]; -#} +sub _insert { + my ($self, $next, $source, $to_insert, $blob_cols, $identity_col) = @_; + + my $updated_cols = $self->$next ($source, $to_insert); + + my $final_row = { + $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}; + + if (not $blob_cols) { + $self->_set_identity_insert($table, 'update') if $is_identity_update; + return $self->next::method(@_); + $self->_unset_identity_insert($table, 'update') if $is_identity_update; + } + +# check that we're not updating a blob column that's also in $where + for my $blob (grep $self->_is_lob_column($source, $_), $source->columns) { + if (exists $where->{$blob} && exists $fields->{$blob}) { + croak +'Update of TEXT/IMAGE column that is also in search condition impossible'; + } + } + +# 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; + + $self->next::method($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) { + $self->_set_identity_insert($table, 'update') if $is_identity_update; + + if ($wantarray) { + @res = $self->next::method(@_); + } + elsif (defined $wantarray) { + $res[0] = $self->next::method(@_); + } + else { + $self->next::method(@_); + } + + $self->_unset_identity_insert($table, 'update') if $is_identity_update; + } + + $guard->commit; + + return $wantarray ? @res : $res[0]; +} + +### the insert_bulk stuff stolen from DBI/MSSQL.pm + +sub _set_identity_insert { + my ($self, $table, $op) = @_; + + my $sql = sprintf ( + 'SET IDENTITY_%s %s ON', + (uc($op) || 'INSERT'), + $self->sql_maker->_quote ($table), + ); + + $self->_query_start($sql); + + my $dbh = $self->_get_dbh; + eval { $dbh->do ($sql) }; + my $exception = $@; + $self->_query_end($sql); + + if ($exception) { + $self->throw_exception (sprintf "Error executing '%s': %s", + $sql, + $dbh->errstr, + ); + } +} + +sub _unset_identity_insert { + my ($self, $table, $op) = @_; + + my $sql = sprintf ( + 'SET IDENTITY_%s %s OFF', + (uc($op) || 'INSERT'), + $self->sql_maker->_quote ($table), + ); + + $self->_query_start($sql); + + my $dbh = $self->_get_dbh; + $dbh->do ($sql); + + $self->_query_end($sql); +} + +# for tests +sub _can_insert_bulk { 1 } + +# XXX this should use the DBD::Sybase bulk API, where possible +sub insert_bulk { + my $self = shift; + my ($source, $cols, $data) = @_; + + my $is_identity_insert = (List::Util::first + { $source->column_info ($_)->{is_auto_increment} } + (@{$cols}) + ) + ? 1 + : 0; + + if ($is_identity_insert) { + $self->_set_identity_insert ($source->name); + } + + $self->next::method(@_); + + if ($is_identity_insert) { + $self->_unset_identity_insert ($source->name); + } +} + +### end of stolen insert_bulk section + +# 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) { - $blob_cols{$col} = delete $fields->{$col} - if $self->_is_lob_type($source->column_info($col)->{data_type}); + if ($self->_is_lob_type($source->column_info($col)->{data_type})) { + my $blob_val = delete $fields->{$col}; + if (not defined $blob_val) { + $fields->{$col} = \'NULL'; + } + else { + $fields->{$col} = \"''"; + $blob_cols{$col} = $blob_val unless $blob_val eq ''; + } + } } - return \%blob_cols; + return keys %blob_cols ? \%blob_cols : undef; } sub _update_blobs { - my ($self, $source, $blob_cols, $inserted) = @_; - my $dbh = $self->dbh; + my ($self, $source, $blob_cols, $where) = @_; + + my (@primary_cols) = $source->primary_columns; + + $self->throw_exception('Cannot update TEXT/IMAGE column(s) without a primary key') + unless @primary_cols; - my $table = $source->from; +# 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; - croak "Cannot update TEXT/IMAGE without a primary key!" + $self->throw_exception('Cannot update TEXT/IMAGE column(s) without a primary key') unless @primary_cols; - my $search_cond = join ',' => map "$_ = ?", @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}; -# First update to empty string in case it's NULL, can't update a NULL blob using -# the API. - my $sth = $dbh->prepare_cached( - qq{update $table set $col = '' where $search_cond} - ); - $sth->execute(map $inserted->{$_}, @primary_cols) or die $sth->errstr; - $sth->finish; + my %where = map { ($_, $row{$_}) } @primary_cols; - $sth = $dbh->prepare_cached( - "select $col from $table where $search_cond" - ); - $sth->execute(map $inserted->{$_}, @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" + . $self->_pretty_print (\%where) + ); + } eval { - while ($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; @@ -195,8 +606,17 @@ 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) { + $self->throw_exception ( + 'TEXT/IMAGE operation failed, probably because you are using FreeTDS: ' + . $exception + ); + } else { + $self->throw_exception($exception); + } + } } } @@ -227,6 +647,7 @@ C 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 ". @@ -234,7 +655,7 @@ C columns only have minute precision. $old_dbd_warned = 1; } - $dbh->do('set dateformat mdy'); + $dbh->do('SET DATEFORMAT mdy'); 1; } @@ -242,93 +663,190 @@ C columns only have minute precision. sub datetime_parser_type { "DateTime::Format::Sybase" } -sub _dbh_last_insert_id { - my ($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.) - # sorry, there's no other way! - my $sth = $dbh->prepare_cached("select max($col) from ".$source->from); - return ($dbh->selectrow_array($sth))[0]; +sub _dbh_begin_work { + my $self = shift; + $self->next::method(@_); + if ($self->using_freetds) { + $self->_get_dbh->do('BEGIN TRAN'); + } } -# previous implementation of limited count for Sybase, does not include -# count_grouped. +sub _dbh_commit { + my $self = shift; + if ($self->using_freetds) { + $self->_dbh->do('COMMIT'); + } + return $self->next::method(@_); +} -#sub _copy_attributes_for_count { -# my ($self, $source, $attrs) = @_; -# my %attrs = %$attrs; -# -# # take off any column specs, any pagers, record_filter is cdbi, and no point of ordering a count -# delete @attrs{qw/select as rows offset page order_by record_filter/}; -# -# return \%attrs; -#} -# -#=head2 count -# -#Counts for limited queries are emulated by executing select queries and -#returning the number of successful executions minus the offset. -# -#This is necessary due to the limitations of Sybase. -# -#=cut -# -#sub count { -# my $self = shift; -# my ($source, $attrs) = @_; -# -# my $new_attrs = $self->_copy_attributes_for_count($source, $attrs); -# -# if (exists $attrs->{rows}) { -# my $offset = $attrs->{offset} || 0; -# my $total = $attrs->{rows} + $offset; -# -# my $first_pk = ($source->primary_columns)[0]; -# -# $new_attrs->{select} = $first_pk ? "me.$first_pk" : 1; -# -# my $tmp_rs = $source->resultset_class->new($source, $new_attrs); -# -# $self->dbh->{syb_rowcount} = $total; -# -# my $count = 0; -# $count++ while $tmp_rs->cursor->next; -# -# $self->dbh->{syb_rowcount} = 0; -# -# return $count - $offset; -# } else { -# # overwrite the selector -# $new_attrs->{select} = { count => '*' }; -# -# my $tmp_rs = $source->resultset_class->new($source, $new_attrs); -# my ($count) = $tmp_rs->cursor->next; -# -# # if the offset/rows attributes are still present, we did not use -# # a subquery, so we need to make the calculations in software -# $count -= $attrs->{offset} if $attrs->{offset}; -# $count = $attrs->{rows} if $attrs->{rows} and $attrs->{rows} < $count; -# $count = 0 if ($count < 0); -# -# return $count; -# } -#} +sub _dbh_rollback { + my $self = shift; + if ($self->using_freetds) { + $self->_dbh->do('ROLLBACK'); + } + return $self->next::method(@_); +} + +# savepoint support using ASE syntax + +sub _svp_begin { + my ($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 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 compiled against FreeTDS +(L) to the best of our ability, however it is +recommended that you recompile L against the Sybase Open Client +libraries. They are a part of the Sybase ASE distribution: + +The Open Client FAQ is here: +L. + +Sybase ASE for Linux (which comes with the Open Client libraries) may be +downloaded here: L. + +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. + +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 option from L is +automatically set, which you may enable on connection with +L. The type info +for the Cs is taken from the L +definitions in your Result classes, and are mapped to a Sybase type (if it isn't +already) using a mapping based on L. + +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 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 as it's a +session variable. + +=head1 TRANSACTIONS + +Due to limitations of the TDS protocol, L, or both; you cannot +begin a transaction while there are active cursors. An active cursor is, for +example, a L that has been executed using +C or C but has not been exhausted or +L. + +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, + ... + }); + } + }); + +Transactions done for inserts in C 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 + +=item * L another L + +=item * load the data from your cursor with L + +=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 application, so on connection +the client side setting is set to C<256> (see L.) You +can override it to whatever setting you like in the DSN. + +See +L +for information on changing the setting on the server side. + =head1 DATES See L to setup date formats for L. -=head1 IMAGE AND TEXT COLUMNS +=head1 TEXT/IMAGE COLUMNS + +L compiled with FreeTDS will B allow you to insert or update +C 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 you pass in +L is used to execute the equivalent +C command on connection. See L for a L setting you need to work with C columns. -Due to limitations in L and this driver, it is only possible to -select one C or C column at a time. - -=head1 AUTHORS +=head1 AUTHOR See L.