From: Rafael Kitover <rkitover@cpan.org>
Date: Tue, 28 Jul 2009 04:23:54 +0000 (+0000)
Subject: minor refactoring, cleanups, doc updates
X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=e97a6ee245047f4caabc1d65cd2c94b2c9c436e0;p=dbsrgits%2FDBIx-Class-Historic.git

minor refactoring, cleanups, doc updates
---

diff --git a/lib/DBIx/Class/Storage/DBI/Sybase.pm b/lib/DBIx/Class/Storage/DBI/Sybase.pm
index 555f0d5..35608b0 100644
--- a/lib/DBIx/Class/Storage/DBI/Sybase.pm
+++ b/lib/DBIx/Class/Storage/DBI/Sybase.pm
@@ -5,14 +5,13 @@ use warnings;
 
 use base qw/
     DBIx::Class::Storage::DBI::Sybase::Base
-    DBIx::Class::Storage::DBI
 /;
 use mro 'c3';
 use Carp::Clan qw/^DBIx::Class/;
 use List::Util ();
 
 __PACKAGE__->mk_group_accessors('simple' =>
-    qw/_identity _blob_log_on_update _auto_cast _insert_txn/
+    qw/_identity _blob_log_on_update auto_cast _insert_txn/
 );
 
 =head1 NAME
@@ -36,10 +35,6 @@ without doing a C<SELECT MAX(col)>.
 
 But your queries will be cached.
 
-You need a version of L<DBD::Sybase> compiled with the Sybase OpenClient
-libraries, B<NOT> FreeTDS, for placeholder support. Otherwise your storage will
-be automatically reblessed into C<::NoBindVars>.
-
 A recommended L<DBIx::Class::Storage::DBI/connect_info> setting:
 
   on_connect_call => [['datetime_setup'], ['blob_setup', log_on_update => 0]]
@@ -70,7 +65,7 @@ sub _rebless {
 # get the identity.
       $self->_insert_txn(1);
 
-      if ($self->_using_freetds) {
+      if ($self->using_freetds) {
         carp <<'EOF' unless $ENV{DBIC_SYBASE_FREETDS_NOWARN};
 
 You are using FreeTDS with Sybase.
@@ -80,7 +75,7 @@ support experimental.
 
 TEXT/IMAGE columns will definitely not work.
 
-You are encouraged to recompile DBD::Sybase with the Sybase OpenClient libraries
+You are encouraged to recompile DBD::Sybase with the Sybase Open Client libraries
 instead.
 
 See perldoc DBIx::Class::Storage::DBI::Sybase for more details.
@@ -88,18 +83,20 @@ 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 $self->_placeholders_with_type_conversion_supported) {
-          if ($self->_placeholders_supported) {
-            $self->_auto_cast(1);
+        if (not $self->placeholders_with_type_conversion_supported) {
+          if ($self->placeholders_supported) {
+            $self->auto_cast(1);
           } else {
             $self->ensure_class_loaded($no_bind_vars);
             bless $self, $no_bind_vars;
             $self->_rebless;
           }
         }
-      }
 
-      if (not $self->dbh->{syb_dynamic_supported}) {
+        $self->set_textsize; # based on LongReadLen in connect_info
+
+      } elsif (not $self->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;
@@ -119,7 +116,7 @@ sub _populate_dbh {
 
   $self->next::method(@_);
 
-  if (not $self->_using_freetds) {
+  if (not $self->using_freetds) {
     $self->_dbh->{syb_chained_txn} = 1;
   } else {
     if ($self->_dbh_autocommit) {
@@ -159,6 +156,33 @@ sub connect_call_blob_setup {
     if exists $args{log_on_update};
 }
 
+=head2 connect_call_set_auto_cast
+
+In some configurations (usually with L</FreeTDS>) statements with values bound
+to columns or conditions that are not strings will throw implicit type
+conversion errors. For L</FreeTDS> this is automatically detected, and this
+option is set.
+
+It converts placeholders to:
+
+  CAST(? as $type)
+
+the type is taken from the L<DBIx::Class::ResultSource/data_type> setting from
+your Result class, and mapped to a Sybase type using a mapping based on
+L<SQL::Translator> if necessary.
+
+This setting can also be set outside of
+L<DBIx::Class::Storage::DBI/connect_info> at any time using:
+
+  $schema->storage->auto_cast(1);
+
+=cut
+
+sub connect_call_set_auto_cast {
+  my $self = shift;
+  $self->auto_cast(1);
+}
+
 sub _is_lob_type {
   my $self = shift;
   my $type = shift;
@@ -178,7 +202,7 @@ sub _prep_for_execute {
 #
 # If we're using ::NoBindVars, there are no binds by this point so this code
 # gets skippeed.
-  if ($self->_auto_cast && @$bind) {
+  if ($self->auto_cast && @$bind) {
     my $new_sql;
     my @sql_part = split /\?/, $sql;
     my $col_info = $self->_resolve_column_info($ident,[ map $_->[0], @$bind ]);
@@ -426,7 +450,7 @@ sub _insert_blobs {
     my $exception = $@;
     $sth->finish if $sth;
     if ($exception) {
-      if ($self->_using_freetds) {
+      if ($self->using_freetds) {
         croak
 "TEXT/IMAGE operation failed, probably because you're using FreeTDS: " .
 $exception;
@@ -464,6 +488,7 @@ 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 ".
@@ -471,7 +496,7 @@ C<SMALLDATETIME> columns only have minute precision.
       $old_dbd_warned = 1;
     }
 
-    $dbh->do('set dateformat mdy');
+    $dbh->do('SET DATEFORMAT mdy');
 
     1;
   }
@@ -479,33 +504,34 @@ C<SMALLDATETIME> columns only have minute precision.
 
 sub datetime_parser_type { "DateTime::Format::Sybase" }
 
-# ->begin_work and such have no effect with FreeTDS
+# ->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;
-  if (not $self->_using_freetds) {
-    return $self->next::method(@_);
-  } else {
+  $self->next::method(@_);
+  if ($self->using_freetds) {
     $self->dbh->do('BEGIN TRAN');
   }
 }
 
 sub _dbh_commit {
   my $self = shift;
-  if (not $self->_using_freetds) {
-    return $self->next::method(@_);
-  } else {
+  if ($self->using_freetds) {
     $self->_dbh->do('COMMIT');
   }
+  return $self->next::method(@_);
 }
 
 sub _dbh_rollback {
   my $self = shift;
-  if (not $self->_using_freetds) {
-    return $self->next::method(@_);
-  } else {
+  if ($self->using_freetds) {
     $self->_dbh->do('ROLLBACK');
   }
+  return $self->next::method(@_);
 }
 
 # savepoint support using ASE syntax
@@ -527,15 +553,47 @@ sub _svp_rollback {
 
 1;
 
+=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
+conversion errors for anything that's not expecting a string. In such a case,
+the C<auto_cast> option is automatically set, which you may enable yourself with
+L</connect_call_set_auto_cast> (see the description of that method for more
+details.)
+
+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 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>
@@ -546,17 +604,25 @@ 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.
 
-C<< $dbh->{LongReadLen} >> will also not work with FreeTDS use:
+Setting C<< $dbh->{LongReadLen} >> will also not work with FreeTDS use either:
+
+  $schema->storage->dbh->do("SET TEXTSIZE $bytes");
 
-  $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.
 
diff --git a/lib/DBIx/Class/Storage/DBI/Sybase/Base.pm b/lib/DBIx/Class/Storage/DBI/Sybase/Base.pm
index 1faec6c..05c2336 100644
--- a/lib/DBIx/Class/Storage/DBI/Sybase/Base.pm
+++ b/lib/DBIx/Class/Storage/DBI/Sybase/Base.pm
@@ -1,5 +1,4 @@
-package # hide from PAUSE
-    DBIx::Class::Storage::DBI::Sybase::Base;
+package DBIx::Class::Storage::DBI::Sybase::Base;
 
 use strict;
 use warnings;
@@ -12,6 +11,15 @@ use mro 'c3';
 DBIx::Class::Storage::DBI::Sybase::Base - Common functionality for drivers using
 DBD::Sybase
 
+=head1 DESCRIPTION
+
+This is the base class for L<DBIx::Class::Storage::DBI::Sybase> and
+L<DBIx::Class::Storage::DBI::Sybase::Microsoft_SQL_Server>. It provides some
+utility methods related to L<DBD::Sybase> and the supported functions of the
+database you are connecting to.
+
+=head1 METHODS
+
 =cut
 
 sub _ping {
@@ -27,7 +35,14 @@ sub _ping {
   return $@ ? 0 : 1;
 }
 
-sub _placeholders_supported {
+=head2 placeholders_supported
+
+Whether or not string placeholders work. Does not check for implicit conversion
+errors, see L</placeholders_with_type_conversion_supported>.
+
+=cut
+
+sub placeholders_supported {
   my $self = shift;
   my $dbh  = $self->_dbh;
 
@@ -35,16 +50,22 @@ sub _placeholders_supported {
 # There's also $dbh->{syb_dynamic_supported} but it can be inaccurate for this
 # purpose.
     local $dbh->{PrintError} = 0;
+    local $dbh->{RaiseError} = 1;
     $dbh->selectrow_array('select ?', {}, 1);
   };
 }
 
-sub _placeholders_with_type_conversion_supported {
+=head2 placeholders_with_type_conversion_supported 
+
+=cut
+
+sub placeholders_with_type_conversion_supported {
   my $self = shift;
   my $dbh  = $self->_dbh;
 
   return eval {
     local $dbh->{PrintError} = 0;
+    local $dbh->{RaiseError} = 1;
 # this specifically tests a bind that is NOT a string
     $dbh->selectrow_array('select 1 where 1 = ?', {}, 1);
   };
@@ -66,12 +87,41 @@ sub _set_max_connect {
   }
 }
 
-sub _using_freetds {
+=head2 using_freetds
+
+Whether or not L<DBD::Sybase> was compiled against FreeTDS. If false, it means
+the Sybase OpenClient libraries were used.
+
+=cut
+
+sub using_freetds {
   my $self = shift;
 
   return $self->_dbh->{syb_oc_version} =~ /freetds/i;
 }
 
+=head2 set_textsize
+
+When using FreeTDS and/or MSSQL, C<< $dbh->{LongReadLen} >> is not available,
+use this function instead. It does:
+
+  $dbh->do("SET TEXTSIZE $bytes");
+
+Takes the number of bytes, or uses the C<LongReadLen> value from your
+L<DBIx::Class/connect_info> if omitted.
+
+=cut
+
+sub set_textsize {
+  my $self = shift;
+  my $text_size = shift ||
+    eval { $self->_dbi_connect_info->[-1]->{LongReadLen} };
+
+  return unless defined $text_size;
+
+  $self->_dbh->do("SET TEXTSIZE $text_size");
+}
+
 1;
 
 =head1 AUTHORS
diff --git a/lib/DBIx/Class/Storage/DBI/Sybase/Microsoft_SQL_Server.pm b/lib/DBIx/Class/Storage/DBI/Sybase/Microsoft_SQL_Server.pm
index b0462f9..1fe11f0 100644
--- a/lib/DBIx/Class/Storage/DBI/Sybase/Microsoft_SQL_Server.pm
+++ b/lib/DBIx/Class/Storage/DBI/Sybase/Microsoft_SQL_Server.pm
@@ -17,12 +17,10 @@ sub _rebless {
 # LongReadLen doesn't work with MSSQL through DBD::Sybase, and the default is
 # huge on some versions of SQL server and can cause memory problems, so we
 # fix it up here.
-  my $dbh = $self->_dbh;
-
-  my $text_size = eval { $self->_dbi_connect_info->[-1]->{LongReadLen} } ||
-    32768; # the DBD::Sybase default
-
-  $dbh->do("set textsize $text_size");
+  $self->set_textsize(
+    eval { $self->_dbi_connect_info->[-1]->{LongReadLen} } ||
+    32768 # the DBD::Sybase default
+  );
 }
 
 1;
diff --git a/lib/DBIx/Class/Storage/DBI/Sybase/NoBindVars.pm b/lib/DBIx/Class/Storage/DBI/Sybase/NoBindVars.pm
index 4d05295..78bf807 100644
--- a/lib/DBIx/Class/Storage/DBI/Sybase/NoBindVars.pm
+++ b/lib/DBIx/Class/Storage/DBI/Sybase/NoBindVars.pm
@@ -72,17 +72,8 @@ without placeholder support
 
 =head1 DESCRIPTION
 
-If you're using this driver than your version of Sybase does not support
-placeholders, or your version of L<DBD::Sybase> was compiled with FreeTDS rather
-than the Sybase OpenClient libraries. You can check with:
-
-  $dbh->{syb_dynamic_supported}
-
-To see if you are using FreeTDS, run:
-
-  perl -MDBI -le 'my $dbh = DBI->connect($dsn, $user, $pass); print $dbh->{syb_oc_version}'
-
-You will get a warning on startup if you're using FreeTDS in any case.
+If you're using this driver than your version of Sybase, or the libraries you
+use to connect to it, do not support placeholders.
 
 You can also enable this driver explicitly using:
 
@@ -95,7 +86,7 @@ $sth->execute >> for details on the pros and cons of using placeholders.
 
 One advantage of not using placeholders is that C<select @@identity> will work
 for obtainging the last insert id of an C<IDENTITY> column, instead of having to
-do C<select max(col)> as the base Sybase driver does.
+do C<select max(col)> in a transaction as the base Sybase driver does.
 
 When using this driver, bind variables will be interpolated (properly quoted of
 course) into the SQL query itself, without using placeholders.
diff --git a/t/746sybase.t b/t/746sybase.t
index f09f16a..9f52894 100644
--- a/t/746sybase.t
+++ b/t/746sybase.t
@@ -76,7 +76,7 @@ SQL
 # so we start unconnected
   $schema->storage->disconnect;
 
-# inserts happen in a txn, so we make sure they can nest
+# inserts happen in a txn, so we make sure it still works inside a txn too
   $schema->txn_begin;
 
 # test primary key handling
@@ -138,7 +138,7 @@ SQL
 # mostly stolen from the blob stuff Nniuq wrote for t/73oracle.t
   SKIP: {
     skip 'TEXT/IMAGE support does not work with FreeTDS', 12
-      if $schema->storage->_using_freetds;
+      if $schema->storage->using_freetds;
 
     my $dbh = $schema->storage->dbh;
     {
@@ -161,7 +161,7 @@ SQL
 
     my $maxloblen = length $binstr{'large'};
     
-    if (not $schema->storage->_using_freetds) {
+    if (not $schema->storage->using_freetds) {
       $dbh->{'LongReadLen'} = $maxloblen * 2;
     } else {
       $dbh->do("set textsize ".($maxloblen * 2));